ADF7012BRU-REEL [ADI]

Multichannel ISM Band FSK/GFSK/OOK/GOOK/ASK Transmitter; 多通道ISM频段FSK / GFSK / OOK / GOOK / ASK发射器
ADF7012BRU-REEL
型号: ADF7012BRU-REEL
厂家: ADI    ADI
描述:

Multichannel ISM Band FSK/GFSK/OOK/GOOK/ASK Transmitter
多通道ISM频段FSK / GFSK / OOK / GOOK / ASK发射器

ISM频段
文件: 总28页 (文件大小:893K)
中文:  中文翻译
下载:  下载PDF数据表文档文件
Multichannel ISM Band  
FSK/GFSK/OOK/GOOK/ASK Transmitter  
ADF7012  
FEATURES  
GENERAL DESCRIPTION  
Single-chip, low power UHF transmitter  
75 MHz to 1 GHz frequency operation  
Multichannel operation using Frac-N PLL  
2.3 V to 3.6 V operation  
On-board regulator—stable performance  
Programmable output power:  
16 dBm to +14 dBm, 0.4 dB steps  
Data rates: dc to 179.2 kbps  
The ADF7012 is a low power FSK/GFSK/OOK/GOOK/ASK  
UHF transmitter designed for short range devices (SRDs). The  
output power, output channels, deviation frequency, and mod-  
ulation type are programmable by using four, 32-bit registers.  
The fractional-N PLL and VCO with external inductor enable  
the user to select any frequency in the 75 MHz to 1 GHz band.  
The fast lock times of the fractional-N PLL make the ADF7012  
suitable in fast frequency hopping systems. The fine frequency  
deviations available and PLL phase noise performance facilitates  
narrow-band operation.  
Low current consumption:  
868 MHz, 10 dBm, 21 mA  
433 MHz, 10 dBm, 17 mA  
315 MHz, 0 dBm, 10 mA  
There are five selectable modulation schemes: binary frequency  
shift keying (FSK), Gaussian frequency shift keying (GFSK),  
binary on-off keying (OOK), Gaussian on-off keying (GOOK),  
and amplitude shift keying (ASK). In the compensation register,  
the output can be moved in <1 ppm steps so that indirect com-  
pensation for frequency error in the crystal reference can be  
made.  
Programmable low battery voltage indicator  
24-lead TSSOP  
APPLICATIONS  
Low cost wireless data transfer  
Security systems  
RF remote controls  
Wireless metering  
A simple 3-wire interface controls the registers. In power-down,  
the part has a typical quiescent current of <0.1 μA.  
Secure keyless entry  
FUNCTIONAL BLOCK DIAGRAM  
C
REG  
PRINTED  
INDUCTOR  
CLK  
CPV  
CP  
GND  
OUT  
DD  
OSC1  
OSC2  
L1  
L2  
C
VCO  
V
DD  
OOK\ASK  
PA  
÷CLK  
VCO  
RF  
OUT  
÷R  
PFD/  
CHARGE  
PUMP  
RF GND  
DV  
DD  
D
C
REG  
GND  
LDO  
REGULATOR  
+FRACTIONAL N  
OOK\ASK  
FSK\GFSK  
TxCLK  
Σ-∆  
TxDATA  
PLL LOCK  
DETECT  
MUXOUT  
LE  
DATA  
CLK  
FREQUENCY  
COMPENSATION  
MUXOUT  
SERIAL  
INTERFACE  
R
SET  
BATTERY  
MONITOR  
CENTER  
FREQUENCY  
CE  
A
GND  
Figure 1.  
Rev. 0  
Information furnished by Analog Devices is believed to be accurate and reliable.  
However, no responsibility is assumed by Analog Devices for its use, nor for any  
infringements of patents or other rights of third parties that may result from its use.  
Specifications subject to change without notice. No license is granted by implication  
or otherwise under any patent or patent rights of Analog Devices. Trademarks and  
registered trademarks are the property of their respective owners.  
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.  
Tel: 781.329.4700  
Fax: 781.326.8703  
www.analog.com  
© 2004 Analog Devices, Inc. All rights reserved.  
ADF7012  
TABLE OF CONTENTS  
Specifications..................................................................................... 3  
GOOK Modulation.................................................................... 15  
Output Divider ........................................................................... 16  
MUXOUT Modes....................................................................... 16  
Theory of Operation ...................................................................... 17  
Choosing the External Inductor Value.................................... 17  
Choosing the Crystal/PFD Value............................................. 17  
Tips on Designing the Loop Filter ........................................... 17  
PA Matching................................................................................ 18  
Transmit Protocol and Coding Considerations ..................... 18  
Application Examples .................................................................... 19  
315 MHz Operation................................................................... 20  
433 MHz Operation................................................................... 21  
868 MHz Operation................................................................... 22  
915 MHz Operation................................................................... 23  
Register Descriptions..................................................................... 24  
R Register..................................................................................... 24  
N-Counter Latch ........................................................................ 25  
Modulation Register .................................................................. 26  
Function Register ....................................................................... 27  
Outline Dimensions....................................................................... 28  
Ordering Guide .......................................................................... 28  
Timing Characteristics..................................................................... 5  
Absolute Maximum Ratings............................................................ 6  
Transistor Count ........................................................................... 6  
ESD Caution.................................................................................. 6  
Pin Configuration and Function Descriptions............................. 7  
Typical Performance Characteristics ............................................. 8  
315 MHz ........................................................................................ 8  
433 MHz ........................................................................................ 9  
868 MHz ...................................................................................... 10  
915 MHz ...................................................................................... 11  
Circuit Description......................................................................... 12  
PLL Operation ............................................................................ 12  
Crystal Oscillator........................................................................ 12  
Crystal Compensation Register................................................ 12  
Clock Out Circuit....................................................................... 12  
Loop Filter ................................................................................... 13  
Voltage-Controlled Oscillator (VCO) ..................................... 13  
Voltage Regulators ...................................................................... 13  
FSK Modulation.......................................................................... 13  
GFSK Modulation ...................................................................... 14  
Power Amplifier.......................................................................... 14  
REVISION HISTORY  
10/04—Revision 0: Initial Version  
Rev. 0 | Page 2 of 28  
ADF7012  
SPECIFICATIONS  
DVDD = 2.3 V – 3.6 V; AGND = DGND = 0 V; TA = TMIN to TMAX, unless otherwise noted. Operating temperature range is −40°C to +85°C.  
Table 1.  
Parameter  
B Version  
Unit  
Conditions/Comments  
RF OUTPUT CHARACTERISTICS  
Operating Frequency  
75/1000  
FRF/128  
MHz min/max  
Hz min  
VCO range adjustable using external inductor;  
divide-by-2, -4, -8 options may be required  
Phase Frequency Detector  
MODULATION PARAMETERS  
Data Rate FSK/GFSK  
179.2  
64  
kbps  
Kbps  
Using 1 MHz loop bandwidth  
Based on US FCC 15.247 specfications for ACP; higher  
data rates are achievable depending on local regulations  
For example, 10 MHz PFD – deviation min = 610 Hz  
For example, 10 MHz PFD – deviation max = 311.7 kHz  
Data Rate ASK/OOK  
Deviation FSK/GFSK  
PFD/214  
511 × PFD/214  
0.5  
Hz min  
Hz max  
typ  
GFSK BT  
ASK Modulation Depth  
OOK Feedthrough (PA Off)  
25  
−40  
−80  
dB max  
dBm typ  
dBm typ  
FRF = Fvco  
FRF = Fvco/2  
POWER AMPLIFIER PARAMETERS  
Max Power Setting, DVDD = 3.6 V  
Max Power Setting, DVDD = 3.0 V  
Max Power Setting, DVDD = 2.3 V  
Max Power Setting, DVDD = 3.6 V  
Max Power Setting, DVDD = 3.0 V  
Max Power Setting, DVDD = 2.3 V  
PA Programmability  
14  
dBm  
dBm  
dBm  
dBm  
dBm  
dBm  
dB typ  
FRF = 915 MHz, PA is matched into 50 Ω  
FRF = 915 MHz, PA is matched into 50 Ω  
FRF = 915 MHz, PA is matched into 50 Ω  
FRF = 433 MHz, PA is matched into 50 Ω  
FRF = 433 MHz, PA is matched into 50 Ω  
FRF = 433 MHz, PA is matched into 50 Ω  
PA output = −20 dBm to +13 dBm  
13.5  
12.5  
14.5  
14  
13  
0.4  
POWER SUPPLIES  
DVDD  
2.3/3.6  
V min/V max  
Current Comsumption  
315 MHz, 0 dBm/5 dBm  
433 MHz, 0 dBm/10 dBm  
8/14  
mA typ  
mA typ  
mA typ  
mA typ  
mA min/max  
µA typ  
µA typ  
DVDD = 3.0 V, PA is matched into 50 Ω, IVCO = min  
VCO current consumption is programmable  
10/18  
14/21/32  
16/24/35  
1/8  
190  
280  
868 MHz, 0 dBm/10 dBm/14 dBm  
915 MHz, 0 dBm/10 dBm/14 dBm  
VCO Current Consumption  
Crystal Oscillator Current Consumption  
Regulator Current Consumption  
Power-Down Current  
0.1/1  
µA typ/max  
REFERENCE INPUT  
Crystal Reference Frequency  
3.4/26  
3.4/26  
MHz min/max  
MHz min/max  
ms typ  
Single-Ended Reference Frequency  
Crystal Power-On Time 3.4 MHz/26 MHz 1.8/2.2  
Single-Ended Input Level CMOS Levels  
CE to Clock Enable Valid  
Refer to the LOGIC INPUTS parameter. Applied to OSC 2 –  
oscillator circuit disabled.  
Rev. 0 | Page 3 of 28  
 
ADF7012  
Parameter  
B Version  
Unit  
Conditions/Comments  
PHASE-LOCKED LOOP PARAMETERS  
VCO Gain  
315MHz  
433MHz  
868MHz  
22  
MHz/V typ  
MHz/V typ  
MHz/V typ  
MHz/V typ  
V min/max  
dBc  
VCO divide-by-2 active  
VCO divide-by-2 active  
24  
80  
915MHz  
88  
VCO Tuning Range  
Spurious (IVCO Min/Max)  
Charge Pump Current  
Setting [00]  
0.3/2.0  
−65/−70  
IVCO is programmable  
0.3  
0.9  
1.5  
2.1  
mA typ  
mA typ  
mA typ  
mA typ  
Refering to DB[7:6] in Function Register  
Refering to DB[7:6] in Function Register  
Refering to DB[7:6] in Function Register  
Refering to DB[7:6] in Function Register  
Setting [01]  
Setting [10]  
Setting [11]  
Phase Noise (In band)1  
315MHz  
−85  
−83  
−80  
−80  
dBc/Hz typ  
dBc/Hz typ  
dBc/Hz typ  
dBc/Hz typ  
PFD = 10 MHz, 5 kHz offset, IVCO = 2 mA  
PFD = 10 MHz, 5 kHz offset, IVCO = 2 mA  
PFD = 10 MHz, 5 kHz offset, IVCO = 3 mA  
PFD = 10 MHz, 5 kHz offset, IVCO = 3 mA  
433MHz  
868MHz  
915MHz  
Phase Noise (Out of Band)1  
315MHz  
−103  
−104  
−115  
−114  
−20  
dBc/Hz typ  
dBc/Hz typ  
dBc/Hz typ  
dBc/Hz typ  
dBc typ  
PFD = 10 MHz, 1 MHz offset, IVCO = 2 mA  
PFD = 10 MHz, 1 MHz offset, IVCO = 2 mA  
PFD = 10 MHz, 1 MHz offset, IVCO = 3 mA  
PFD = 10 MHz, 1 MHz offset, IVCO = 3 mA  
FRF = FVCO  
433MHz  
868MHz  
915MHz  
Harmonic Content (Second)2  
Harmonic Content (Third)2  
Harmonic Content (Others)2  
Harmonic Content (Second)2  
Harmonic Content (Third)2  
Harmonic Content (Others)2  
LOGIC INPUTS  
−30  
dBc typ  
−27  
dBc typ  
−24  
dBc typ  
FRF = FVCO/N (where N = 2, 4, 8)  
−14  
dBc typ  
−19  
dBc typ  
Input High Voltage,VINH  
0.7 × DVDD  
V min  
Input Low Voltage, VINL  
Input Current, IINH/IINL  
Input Capacitance, CIN  
LOGIC OUTPUTS  
0.2 × DVDD  
V max  
µA max  
pF max  
1
4.0  
Output High Voltage, VOH  
DVDD − 0.4  
500  
V min  
CMOS output chosen  
IOL = 500 µA  
Output High Current, IOH,  
Output Low Voltage, VOL  
µA max  
V max  
0.4  
1 Measurements made with NFRAC = 2048.  
2 Measurements made without harmonic filter.  
Rev. 0 | Page 4 of 28  
 
 
 
 
ADF7012  
TIMING CHARACTERISTICS  
DVDD = 3 V 10ꢀ; AGND = DGND = 0 V; TA = TMIN to TMAX, unless otherwise noted.  
Table 2.  
Parameter  
Limit at TMIN to TMAX (B Version)  
Unit  
Test Conditions/Comments  
LE setup time  
Data-to-clock setup time  
Data-to-clock hold time  
Clock high duration  
Clock low duration  
t1  
t2  
t3  
t4  
t5  
t6  
t7  
20  
10  
10  
25  
25  
10  
20  
ns min  
ns min  
ns min  
ns min  
ns min  
ns min  
ns min  
Clock –to-LE setup time  
LE pulse width  
t4  
t5  
CLOCK  
t2  
t3  
DB1  
DB0 (LSB)  
(CONTROL BIT C1)  
DB23 (MSB)  
DB22  
DB2  
DATA  
LE  
(CONTROL BIT C2)  
t7  
t1  
t6  
LE  
Figure 2. Timing Diagram  
Rev. 0 | Page 5 of 28  
 
ADF7012  
ABSOLUTE MAXIMUM RATINGS  
TA = 25°C, unless otherwise noted.  
Stresses above those listed under Absolute Maximum Ratings  
may cause permanent damage to the device. This is a stress  
rating only; functional operation of the device at these or any  
other conditions above those listed in the operational sections  
of this specification is not implied. Exposure to absolute  
maximum rating conditions for extended periods may affect  
device reliability.  
Table 3.  
Parameter  
Rating  
DVDD to GND  
(GND = AGND = DGND = 0 V)  
−0.3 V to +3.9 V  
Digital I/O Voltage to GND  
Analog I/O Voltage to GND  
Operating Temperature Range  
Maximum Junction Temperature  
TSSOP θJA Thermal Impedance  
Lead Temperature, Soldering  
Vapor Phase (60 sec)  
−0.3 V to DVDD + 0.3 V  
−0.3 V to DVDD + 0.3 V  
150°C  
150.4°C/W  
This device is a high performance RF integrated circuit with an  
ESD rating of 1 kV and it is ESD sensitive. Proper precautions  
should be taken for handling and assembly.  
215°C  
220°C  
Infrared (15 sec)  
TRANSISTOR COUNT  
35819 (CMOS)  
ESD CAUTION  
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on  
the human body and test equipment and can discharge without detection. Although this product features  
proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy  
electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance  
degradation or loss of functionality.  
Rev. 0 | Page 6 of 28  
 
ADF7012  
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS  
DV  
DD  
1
24  
C
REG2  
C
2
23  
R
REG1  
SET  
CP  
3
22 AGND  
OUT  
TSSOP  
TxDATA  
4
21 DV  
20 RF  
19 RF  
DD  
TxCLK  
MUXOUT  
DGND  
5
OUT  
GND  
ADF7012  
TOP VIEW  
(Not to Scale)  
6
7
18 VCO  
IN  
OSC1  
8
17 C  
VCO  
OSC2  
9
16 L2  
15 L1  
14 CE  
13 LE  
CLK  
10  
OUT  
CLK 11  
DATA 12  
Figure 3.  
Table 4. Pin Functional Descriptions  
Pin No. Mnemonic Description  
1
2
3
DVDD  
CREG1  
CPOUT  
Positive Supply for the Digital Circuitry. This must be between 2.3 V and 3.6 V. Decoupling capacitors to the analog  
ground plane should be placed as close as possible to this pin.  
A 2.2 µF capacitor should be added at CREG to reduce regulator noise and improve stability. A reduced capacitor  
improves regulator power-on time, but may cause higher spurious noise.  
Charge Pump Output. This output generates current pulses that are integrated in the loop filter. The integrated  
current changes the control voltage on the input to the VCO.  
4
5
TxDATA  
TxCLK  
Digital Data to Be Transmitted is inputted on this pin.  
GFSK and GOOK only. This clock output is used to synchronize microcontroller data to the TxDATA pin of the  
ADF7012. The clock is provided at the same frequency as the data rate. The microcontroller updates TxDATA on  
the falling edge of TxCLK. The rising edge of TxCLK is used to sample TxDATA at the midpoint of each bit.  
6
MUXOUT  
Provides the Lock_Detect Signal. This determines if the PLL is locked to the correct frequency and also monitors  
battery voltage. Other signals include Regulator_Ready, which indicates the status of the serial interface regulator.  
7
8
9
DGND  
OSC1  
OSC2  
Ground for Digital Section.  
The reference crystal should be connected between this pin and OSC2.  
The reference crystal should be connected between this pin and OSC1. A TCXO reference may be used, by driving  
this pin with CMOS levels, and powering down the crystal oscillator bit in software.  
10  
11  
12  
13  
14  
15  
CLKOUT  
CLK  
DATA  
LE  
A divided-down version of the crystal reference with output driver. The digital clock output may be used to drive  
several other CMOS inputs, such as a microcontroller clock. The output has a 50:50 mark-space ratio.  
Serial Clock Input. This serial clock is used to clock in the serial data to the registers. The data is latched into the  
32-bit shift register on the CLK rising edge. This input is a high impedance CMOS input.  
Serial Data Input. The serial data is loaded MSB first with the two LSBs being the control bits. This is a high  
impedance CMOS input.  
Load Enable, CMOS Input. When LE goes high, the data stored in the shift registers is loaded into one of the four  
latches, the latch being selected using the control bits.  
Chip Enable. Bringing CE low puts the ADF7012 into complete power-down, drawing < 1uA. Register values are  
lost when CE is low and the part must be reprogrammed once CE is brought high.  
Connected to external printed or discrete inductor. See Choosing the External Inductor Value for advice on the  
value of the inductor to be connected between L1 and L2.  
CE  
L1  
16  
17  
L2  
CVCO  
Connected to external printed or discrete inductor.  
A 220 nF capacitor should be tied between the CVCO and CREG2 pins. This line should run underneath the ADF7012.  
This capacitor is necessary to ensure stable VCO operation.  
18  
VCOIN  
The tuning voltage on this pin determines the output frequency of the voltage controlled oscillator (VCO). The  
higher the tuning voltage, the higher the output frequency.  
19  
20  
RFGND  
RFOUT  
Ground for Output Stage of Transmitter.  
The modulated signal is available at this pin. Output power levels are from –16 dBm to +12 dBm. The output  
should be impedance matched using suitable components to the desired load. See the PA Matching section.  
21  
DVDD  
Voltage supply for VCO and PA section. This should have the same supply as DVDD Pin 1, and should be between  
2.3 V and 3.6 V. Place decoupling capacitors to the analog ground plane as close as possible to this pin.  
22  
23  
24  
AGND  
RSET  
CREG2  
Ground Pin for the RF Analog Circuitry.  
External Resistor to set charge pump current and some internal bias currents. Use 3.6 kV as default.  
Add a 470 nF capacitor at CREG to reduce regulator noise and improve stability. A reduced capacitor improves  
regulator power-on time and phase noise, but may have stability issues over the supply and temperature.  
Rev. 0 | Page 7 of 28  
 
ADF7012  
TYPICAL PERFORMANCE CHARACTERISTICS  
315 MHZ  
RBW  
VBW  
SWT  
RF ATT 30dB  
–60  
1MHz  
1MHz  
17.5ms  
REF LVL  
5dBm  
0.27dBm  
308.61723447MHz  
= NORMAL  
FREQUENCY = 9.08 kHz  
LEVEL = –84.47dBc/Hz  
UNIT  
dBm  
5
0
–70  
1
A
3
–80  
–90  
–10  
–20  
–30  
1MA  
4
2
–100  
–110  
–120  
–40  
–50  
D1 –41.5dBm  
–11.48dBm  
–60  
–70  
–130  
–140  
1 [T1]  
2 [T1]  
0.27dBm  
3 [T1]  
4 [T1]  
308.61723447MHz  
–35.43dBm  
939.87975952MHz  
–34.11dBm  
–80  
631.26252505MHz  
1.26252505GHz  
–90  
–95  
1.0k  
10.0k  
100.0k  
PHASE NOISE (Hz)  
1.0M  
10.0M  
CENTER 3.5MHz  
700MHz/  
SPAN 7GHz  
Figure 4. Phase Noise Response—DVDD = 3.0 V, ICP = 0.86 mA  
IVCO = 2.0 mA, FOUT = 315 MHz, PFD = 3.6864 MHZ, PA Bias = 5.5 mA  
Figure 7. Harmonic Response, RFOUT Matched to 50 Ω, No Filter  
RBW  
VBW  
SWT  
RF ATT 30dB  
5kHz  
5kHz  
500ms  
RBW  
VBW  
SWT  
RF ATT 30dB  
1MHz  
1MHz  
17.5ms  
REF LVL  
5dBm  
0.45dBm  
REF LVL  
5dBm  
0.18dBm  
308.61723447MHz  
315.05060120MHz  
UNIT  
dBm  
UNIT  
dBm  
5
0
5
0
1
2
1
A
A
–10  
–20  
–30  
SGL  
–10  
–20  
–30  
1MA  
1MA  
–40  
–50  
3
–40  
–50  
D1 –41.5dBm  
–42.93dBm  
2
4
–60  
–70  
–60  
–70  
1 [T1]  
2 [T1]  
0.18dBm  
3 [T1]  
4 [T1]  
–80  
308.61723447MHz  
–50.53dBm  
631.26252505MHz  
939.87975952MHz  
–55.48dBm  
–80  
1.26252505GHz  
–90  
–95  
–90  
–95  
CENTER 315MHz  
50kHz/  
SPAN 500kHz  
CENTER 3.5MHz  
700MHz/  
SPAN 7GHz  
Figure 5. FSK Modulation, Power = 0 dBm, Data Rate = 1 kbps,  
FDEVIATION 50 kHz  
Figure 8. Harmonic Response, Fifth-Order Butterworth Filter  
=
RBW  
RF ATT 30dB  
500kHz  
500kHz  
5ms  
RBW  
VBW  
SWT  
RF ATT 30dB  
5kHz  
5kHz  
500ms  
REF LVL  
5dBm  
0.31dBm  
315.40080160MHz  
VBW  
SWT  
REF LVL  
5dBm  
20.33dBm  
UNIT  
dBm  
26.55310621kHz  
UNIT  
dBm  
5
0
5
0
1
A
A
1
–10  
–20  
–30  
–10  
–20  
–30  
2
3
1MA  
1MA  
–40  
–50  
–40  
–50  
D1 –41.5dBm  
D2 –49dBm  
–60  
–70  
–60  
–70  
1 [T1]  
3 [T1]  
2 [T1]  
–3.49dBm  
315.00012525MHz  
–20.33dB  
–80  
–80  
26.55310621kHz  
–20.85dB  
1 [T1]  
0.31dBm  
315.40080160MHz  
–90  
–95  
–90  
–95  
–27.55511022kHz  
CENTER 315MHz  
40MHz/  
SPAN 400MHz  
CENTER 315MHz  
50kHz/  
SPAN 500kHz  
Figure 6. Spurious Components—Meets FCC Specs  
Figure 9. OOK Modulation, Power = 0 dBm, Data Rate = 10 kbps  
Rev. 0 | Page 8 of 28  
 
ADF7012  
433 MHZ  
RBW  
VBW  
SWT  
RF ATT 40dB  
1 2.00V/ 2 1.00V/  
1.50ms 500µs TRIG'D 1 720mv  
30kHz  
30kHz  
90ms  
REF LVL  
15dBm  
10.01dBm  
433.91158317MHz  
UNIT  
dBm  
15  
10  
1
A
0
–10  
–20  
1MA  
2
1
CLKOUT  
–30  
–40  
D1 –36dBm  
–50  
–60  
CE  
–70  
–80  
–85  
CENTER 433.9500601MHz 3.2MHz/  
SPAN 32MHz  
Figure 10. Crystal Power-On Time, 4 MHz, Time = 1.6 ms  
Figure 13. Spurious Components—Meets ETSI Specs  
–40  
RBW  
VBW  
SWT  
RF ATT 40dB  
1MHz  
1MHz  
17.5ms  
REF LVL  
15dBm  
10.10dBm  
= NORMAL  
FREQUENCY = 393.38 kHz  
LEVEL = –102.34dBc/Hz  
434.86973948MHz  
UNIT  
dBm  
15  
10  
–60  
–80  
1
A
0
–10  
–20  
3
2
–100  
–120  
–140  
–160  
4
1MA  
–30  
–40  
D1 –30dBm  
D1 –36dBm  
–50  
–60  
–180  
–200  
1 [T1]  
2 [T1]  
10.10dBm  
3 [T1]  
4 [T1]  
–5.12dBm  
1.30460922GHz  
–17.57dBm  
434.86973948MHz  
–15.25dBm  
–70  
869.73947896MHz  
1.73947896GHz  
–80  
–85  
1.0k  
10.0k  
100.0k  
PHASE NOISE (Hz)  
1.0M  
10.0M  
CENTER 3.5GHz  
700MHz/  
SPAN 7GHz  
Figure 11. Phase Noise Response—ICP = 2.0 mA, IVCO = 2.0 mA,  
RFOUT = 433.92 MHz, PFD = 4 MHz, PA Bias = 5.5 mA  
Figure 14. Harmonic Response, RFOUT Matched to 50 , No Filter  
RBW  
VBW  
SWT  
RF ATT 40dB  
RBW  
VBW  
SWT  
RF ATT 40dB  
10kHz  
300kHz  
44ms  
1MHz  
1MHz  
17.5ms  
REF LVL  
15dBm  
5.60dBm  
REF LVL  
15dBm  
9.51dBm  
434.86973948MHz  
433.91158317MHz  
UNIT  
dBm  
UNIT  
dBm  
15  
10  
15  
10  
1
A
A
1
0
–10  
–20  
0
–10  
–20  
SGL  
1MA  
1MA  
–30  
–40  
–30  
–40  
2
D1 –30dBm  
D1 –36dBm  
D1 –36dBm  
3
4
–50  
–60  
–50  
–60  
1 [T1]  
2 [T1]  
9.51dBm  
3 [T1]  
4 [T1]  
–43.60dBm  
1.30460922GHz  
–43.44dBm  
434.86973948MHz  
–33.75dBm  
–70  
–70  
869.73947896MHz  
1.73947896GHz  
–80  
–85  
–80  
–85  
START 433.05MHz  
174kHz/  
STOP 434.79kHz  
CENTER 3.5GHz  
700MHz/  
SPAN 7GHz  
Figure 15. Harmonic Response, Fifth-Order Butterworth Filter  
Figure 12. FSK Modulation, Power = 10 dBm, Data Rate = 38.4 kbps, FDEVIATION  
19.28 kHz  
=
Rev. 0 | Page 9 of 28  
 
 
ADF7012  
868 MHZ  
RBW  
VBW  
SWT  
RF ATT 40dB  
0
1MHz  
1MHz  
16ms  
REF LVL  
15dBm  
12.27dBm  
= NORMAL  
FREQUENCY = 251.3 kHz  
LEVEL = –99.39dBc/Hz  
869.33867735MHz  
UNIT  
dBm  
15  
10  
–20  
–40  
1
A
2
0
–10  
–20  
4
3
–60  
1MAX  
1MA  
–80  
–30  
–40  
D1 –30dBm  
–16.88dBm  
–100  
–120  
–140  
–50  
–60  
1 [T1]  
2 [T1]  
12.27dBm  
869.33867735MHz  
–4.00dBm  
3 [T1]  
4 [T1]  
2.59699399GHz  
–15.06dBm  
–70  
–160  
1.0k  
1.72865731GHz  
3.46913828GHz  
–80  
–85  
10.0k  
100.0k  
PHASE NOISE (Hz)  
1.0M  
10.0M  
CENTER 3.8GHz  
640MHz/  
SPAN 6.4GHz  
Figure 16. Phase Noise Response–ICP = 2.5 mA, IVCO = 1.44 mA, RFOUT = 868.95  
MHz, PFD = 4.9152 MHz, Power = 12.5 dBm, PA Bias = Max  
Figure 19. Harmonic Response, RFOUT Matched to 50 , No Filter  
RBW  
VBW  
SWT  
RF ATT  
30dB  
MIXER –20dBm  
UNIT dBm  
RBW  
VBW  
SWT  
RF ATT  
30dB  
MIXER –20dBm  
UNIT dBm  
10kHz  
10kHz  
15ms  
1kHz  
1kHz  
10ms  
REF LVL  
15dBm  
–40.44dBm  
869.20000000MHz  
REF LVL  
15dBm  
10.39dBm  
869.33867735MHz  
15  
10  
15  
10  
2
1
A
A
1 [T1]  
10.39dBm  
869.33867735MHz  
–50.92dBm  
1.72000000GHz  
–50.40dBm  
2.59600000GHz  
LN  
LN  
3 [T1]  
2 [T1]  
0
–10  
–20  
0
–10  
–20  
1MAX  
1MAX  
1MA  
1MA  
–30  
–40  
–30  
–40  
D2 –30dBm  
D2 –36dBm  
1
3
2
–50  
–60  
–50  
–60  
1 [T1]  
2 [T1]  
40.44dBm  
869.20000000MHz  
8.02dBm  
–70  
–70  
868.96673347MHz  
–80  
–85  
–80  
–85  
CENTER 868.944489MHz  
60kHz/  
SPAN 600kHz  
START 3.8GHz  
640MHz/  
SPAN 6.4GHz  
Figure 17. FSK Modulation, Power = 12.5 dBm, Data Rate = 38.4 kbps,  
FDEVIATION 19.2 kHz  
Figure 20. Harmonic Response, Fifth-Order Chebyshev Filter  
=
RBW  
VBW  
SWT  
RF ATT  
30dB  
MIXER –20dBm  
UNIT dBm  
2kHz  
2kHz  
16s  
REF LVL  
15dBm  
12.55dBm  
869.025050100MHz  
15  
10  
1
A
1 [T1]  
12.55dBm  
LN  
869.02505010MHz  
–57.89dBm  
2 [T1]  
3 [T1]  
0
–10  
–20  
859.16695500MHz  
–81.97dBm  
862.00000000MHz  
1MAX  
1MA  
–30  
–40  
D2 –36dBm  
D1 –54dBm  
–50  
–60  
2
–70  
3
START 856.5MHz  
–80  
–85  
2.5MHz/  
STOP 881.5MHz  
Figure 18. Spurious Components—Meets ETSI Specs  
Rev. 0 | Page 10 of 28  
 
ADF7012  
915 MHZ  
–40  
RBW  
VBW  
SWT  
RF ATT 40dB  
50MHz  
50MHz  
6.4s  
REF LVL  
15dBm  
10.25dBm  
= NORMAL  
FREQUENCY = 992.38 kHz  
LEVEL = –102.34dBc/Hz  
907.81563126MHz  
UNIT  
dBm  
15  
10  
–60  
–80  
A
1
0
–10  
–20  
2
–100  
–120  
–140  
–160  
–180  
4
3
1MAX  
1MA  
–30  
–40  
D1 –41.5dBm  
–20.29dBm  
2.74188377GHz  
–17.50dBm  
3.65250501GHz  
–50  
–60  
1 [T1]  
2 [T1]  
10.25dBm  
3 [T1]  
4 [T1]  
907.81563126MHz  
–10.06dBm  
–70  
–200  
1.0k  
10.0k  
100.0k  
1.0M  
10.0M  
1.83126253GHz  
–80  
–85  
PHASE NOISE (Hz)  
CENTER 3.8GHz  
640MHz/  
SPAN 6.4GHz  
Figure 21. Phase Noise Response–ICP = 1.44 mA, IVCO = 3.0 mA, RFOUT = 915.2  
MHz, PFD =10 MHz, Power = 10 dBm, PA Bias = 5.5 mA  
Figure 24. Harmonic Response, RFOUT Matched to 50 , No Filter  
RBW  
VBW  
SWT  
RF ATT 40dB  
RBW  
VBW  
SWT  
RF ATT 40dB  
10kHz  
300kHz  
15ms  
50MHz  
50MHz  
6.4s  
REF LVL  
15dBm  
3.88dBm  
REF LVL  
15dBm  
9.06dBm  
907.81563126MHz  
915.19098196MHz  
UNIT  
dBm  
UNIT  
dBm  
15  
10  
15  
10  
A
A
1
1
0
–10  
–20  
0
–10  
–20  
1MAX  
1MAX  
1MA  
1MA  
–30  
–40  
–30  
–40  
D1 –41.5dBm  
3
4
2
–50  
–60  
–50  
–60  
1 [T1]  
2 [T1]  
9.06dBm  
3 [T1]  
4 [T1]  
–46.22dBm  
2.74188377GHz  
–46.96dBm  
907.81563126MHz  
–48.40dBm  
–70  
–70  
1.83126253GHz  
3.65250501GHz  
–80  
–85  
–80  
–85  
CENTER 915.190982MHz  
50kHz/  
SPAN 500kHz  
CENTER 3.8GHz  
640MHz/  
SPAN 6.4GHz  
Figure 22. FSK Modulation, Power = 10 dBm, Data Rate = 38.4 kbps,  
Fdeviation = 19.2 kHz  
Figure 25. Harmonic Response, Fifth-Order Chebyshev Filter  
RBW  
VBW  
SWT  
RF ATT 40dB  
10kHz  
300kHz  
100ms  
REF LVL  
15dBm  
9.94dBm  
915.23167977MHz  
UNIT  
dBm  
15  
10  
*
A
1
SGL  
0
–10  
–20  
1MA  
–30  
–40  
D1 –41.5dBm  
D1 –49.5dBm  
–50  
–60  
–70  
–80  
–85  
CENTER 915.2MHz  
40MHz/  
SPAN 400MHz  
Figure 23. Spurious Components—Meets FCC Specs  
Rev. 0 | Page 11 of 28  
 
ADF7012  
CIRCUIT DESCRIPTION  
PLL OPERATION  
A fractional-N PLL allows multiple output frequencies to be  
generated from a single-reference oscillator (usually a crystal)  
simply by changing the programmable N value found in the N  
register. At the phase frequency detector (PFD), the reference is  
compared to a divided-down version of the output frequency  
(VCO/N). If VCO/N is too low a frequency, typically the output  
frequency is lower than desired, and the PFD and charge-pump  
combination sends additional current pulses to the loop filter.  
This increases the voltage applied to the input of the VCO.  
Because the VCO of the ADF7012 has a positive frequency vs.  
voltage characteristic, any increase in the Vtune voltage applied  
to the VCO input increases the output frequency at a rate of kV,  
the tuning sensitivity of the VCO (MHz/V). At each interval of  
1/PFD seconds, a comparison is made at the PFD until the PFD  
and charge pump eventually force a state of equilibrium in the  
PLL where PFD frequency = VCO/N. At this point, the PLL can  
be described as locked.  
OSC1  
OSC2  
CP1  
CP2  
Figure 27.  
Two parallel resonant capacitors are required for oscillation at  
the correct frequency—the value of these depend on the crystal  
specification. They should be chosen so that the series value of  
capacitance added to the PCB track capacitance adds to give the  
load capacitance of the crystal, usually 20 pF. Track capacitance  
values vary between 2 pF to 5 pF, depending on board layout.  
Where possible, to ensure stable frequency operation over all  
conditions, capacitors should be chosen so that they have a very  
low temperature coefficient and/or opposite temperature  
coefficients  
CRYSTAL/R  
LOOP FILTER  
R
CRYSTAL COMPENSATION REGISTER  
PFD CP  
FVCO  
VCO  
The ADF7012 features a 15-bit fixed modulus, which allows the  
output frequency to be adjusted in steps of FPFD/15. This fine  
resolution can be used to easily compensate for initial error and  
temperature drift in the reference crystal.  
VCO/N  
N
FADJUST = FSTEP × FEC  
(3)  
Figure 26.  
where FSTEP = FPFD/215 and FEC = Bits F1 to F11 in the R  
Register. Note that the notation is twos compliment, so F11  
represents the sign of the FEC number.  
FCRYSTAL × N  
FOUT  
=
= FPFD × N  
(1)  
(2)  
R
Example  
For a Fractional N PLL  
F
F
F
PFD = 10 MHz  
ADJUST = −11 kHz  
NFRAC  
STEP = 10 MHz/215 = 305.176 Hz  
FOUT = FPFD × N  
+
INT  
212  
FEC = −11 kHz/305.17 Hz = −36 = −(00000100100) =  
11111011100 = 0x7DC  
where NFRAC can be bits M1 to M12 in the fractional N register.  
CLOCK OUT CIRCUIT  
CRYSTAL OSCILLATOR  
The clock out circuit takes the reference clock signal from the  
oscillator section above and supplies a divided-down 50:50  
mark-space signal to the CLKOUT pin. An even divide from  
2 to 30 is available. This divide is set by the DB[19:22] in the R  
register. On power-up, the CLKOUT defaults to divide by 16.  
The on-board crystal oscillator circuitry (Figure 27) allows an  
inexpensive quartz crystal to be used as the PLL reference. The  
oscillator circuit is enabled by setting XOEB low. It is enabled by  
default on power-up and is disabled by bringing CE low. Errors  
in the crystal can be corrected using the error correction  
register within the R register.  
DV  
DD  
CLK  
ENABLE BIT  
OUT  
A single-ended reference may be used instead of a crystal, by  
applying a square wave to the OSC2 pin, with XOEB set high.  
DIVIDER  
1 TO 15  
OSC1  
÷2  
CLK  
OUT  
Figure 28.  
Rev. 0 | Page 12 of 28  
 
ADF7012  
The output buffer to CLKOUT is enabled by setting Bit DB4 in  
the function register high. On power-up, this bit is set high.  
The output buffer can drive up to a 20 pF load with a 10ꢀ rise  
time at 4.8 MHz. Faster edges can result in some spurious  
feedthrough to the output. A small series resistor (50 Ω) can be  
Figure 32 shows the VCO gain over temperature and frequency.  
VCO gain is important in determining the loop filter design—  
predictable changes in VCO gain resulting in a change in the  
loop filter bandwidth can be offset by changing the charge-  
pump current in software.  
used to slow the clock edges to reduce these spurs at FCLK  
.
VCO Bias Current  
VCO bias current may be adjusted using bits VB1 to VB4 in the  
function register. Additional bias current will reduce spurious  
levels, but increase overall current consumption in the part. A  
bias value of 0x5 should ensure oscillation at most frequencies  
and supplies. Settings 0x0, 0xE ,and 0xF are not recommended.  
Setting 0x3 and Setting 0x4 are recommended under most  
conditions. Improved phase noise can be achieved for lower  
bias currents.  
LOOP FILTER  
The loop filter integrates the current pulses from the charge  
pump to form a voltage that tunes the output of the VCO to the  
desired frequency. It also attenuates spurious levels generated by  
the PLL. A typical loop filter design is shown in Figure 29.  
CHARGE  
VCO  
PUMP OUT  
VOLTAGE REGULATORS  
There are two band gap voltage regulators on the ADF7012  
providing a stable 2.25 V internal supply: a 2.2 µF capacitor  
(X5R, NP0) to ground at CREG1 and a 470 nF capacitor at CREG2  
should be used to ensure stability. The internal reference  
ensures consistent performance over all supplies and reduces  
the current consumption of each of the blocks.  
Figure 29.  
In FSK, the loop should be designed so that the loop bandwidth  
(LBW) is a minimum of two to three times the data rate.  
Widening the LBW excessively reduces the time spent jumping  
between frequencies, but results in reduced spurious  
The combination of regulators, band gap reference, and biasing  
typically consume 1.045 mA at 3.0 V and can be powered down  
by bringing the CE line low. The serial interface is supplied by  
Regulator 1, so powering down the CE line causes the contents  
of the registers to be lost. The CE line must be high and the  
regulators must be fully powered on to write to the serial  
interface. Regulator power-on time is typically 100 µs and  
should be taken into account when writing to the ADF7012  
after power-up. Alternatively, regulator status may be monitored  
at the MUXOUT pin once CE has been asserted, because  
MUXOUT defaults to the regulator ready signal. Once  
Regulator_ready is high, the regulator is powered up and the  
serial interface is active.  
attenuation. See the section Tips on Designing the Loop Filter.  
For OOK/ASK systems, a wider loop bandwidth than for FSK  
systems is desirable. The sudden large transition between two  
power levels results in VCO pulling (VCO temporarily goes to  
incorrect frequency) and can cause a wider output spectrum.  
By widening the loop bandwidth a minimum of 10 × data rate,  
VCO pulling is minimized because the loop settles quickly back  
to the correct frequency. The free design tool ADIsimPLL™ can  
be used to design loop filters for the ADI family of transmitters.  
VOLTAGE-CONTROLLED OSCILLATOR (VCO)  
The ADF7012 features an on-chip VCO with an external tank  
inductor, which is used to set the frequency range. The center  
frequency of oscillation is governed by the internal varactor  
capacitance and that of the external inductor combined with the  
bond-wire inductance. An approximation for this is given in the  
Equation 4. For a more accurate selection of the inductor, see  
the section Choosing the External Inductor Value.  
FSK MODULATION  
FSK modulation is performed internally in the PLL loop by  
switching the value of the N register based on the status of the  
TxDATA line. The TxDATA line is sampled at each cycle of the  
PFD block (every 1/FPFD seconds). When TxDATA makes a low-  
to-high transition, an N value representing the deviation  
frequency is added to the N value representing the center  
frequency. Immediately the loop begins to lock to the new  
frequency of FCENTER + FDEVIATION. Conversely, when TxDATA  
makes a high-to-low transition, the N value representing the  
deviation is subtracted from the PLL N value representing the  
1
F
=
(4)  
VCO  
2π (LINT + LEXT )×  
(CVAR + CFIXED  
)
The varactor capacitance can be adjusted in software to increase  
the effective VCO range by writing to bits VA1 and VA2 in the  
R register. Under typical conditions, setting VA1 and VA2 high  
increases the center frequency by reducing the varactor  
capacitance by approximately 1.3 pF.  
center frequency and the loop transitions to FCENTER − FDEVIATION  
.
Rev. 0 | Page 13 of 28  
 
 
ADF7012  
For GFSK and GOOK, the incoming bit stream to be trans-  
mitted needs to be synchronized with an on-chip sampling  
clock which provides one sample per bit to the Gaussian FIR  
filter. To facilitate this, the sampling clock is routed to the  
TxCLK pin where data is fetched from the host microcontroller  
or microprocessor on the falling edge of TxCLK, and the data is  
sampled at the midpoint of each bit on TxCLK’s rising edge.  
Inserting external RC LPFs on TxDATA and TxCLK lines  
creates smoother edge transitions and improves spurious  
performance. As an example, suitable components would be a  
1 kV resistor and 10 nF capacitor for a data rate of 5 kbps.  
PFD/  
CHARGE  
PUMP  
PA STAGE  
4R  
VCO  
FSK DEVIATION  
FREQUENCY  
÷N  
–F  
+F  
DEV  
THIRD-ORDER  
Σ-MODULATOR  
DEV  
TxDATA  
FRACTIONAL-N  
INTEGER-N  
Figure 30.  
I/O  
TxDATA  
ADF7012  
TxCLK  
µC  
The deviation from the center frequency is set using bits D1 to  
D9 in the modulation register. The frequency deviation may be  
set in steps of  
INT  
FETCH  
FETCH  
FETCH  
FETCH  
SAMPLE SAMPLE SAMPLE  
FPFD  
Figure 31. TxCLK/TxDATA Synchronization.  
FSTEP (Hz) =  
(5)  
214  
The number of steps between symbol ‘0’ and symbol ‘1’ is  
determined by the setting for the index counter.  
The deviation frequency is therefore  
FPFD × ModulationNumber  
The GFSK deviation is set up as  
FDEVIATION (Hz) =  
(6)  
214  
where ModulationNumber is set by bits D1 to D9.  
FPFD × 2m  
GFSKDEVIATION (Hz) =  
(7)  
(8)  
212  
The maximum data rate is a function of the PLL lock time (and  
the requirement on FSK spectrum). Because the PLL lock time  
is reduced by increasing the loop-filter bandwidth, highest data  
rates can be achieved for the wider loop filter bandwidths. The  
absolute maximum limit on loop filter bandwidth to ensure  
stability for a fractional-N PLL is FPFD/7. For a 20 MHz PFD  
frequency, the loop bandwidth could be as high as 2.85 MHz.  
FSK modulation is selected by setting bits S1 and S2 in the  
modulation register low.  
where m is the mod control (Bits MC1 to MC3 in the  
modulation register).  
The GFSK sampling clock samples data at the data rate:  
FPFD  
DataRate (bps) =  
DividerFactor × IndexCounter  
where DividerFactor can be bits D1 to D7, and IndexCounter  
can be bits IC1 and IC2 in the modulation register.  
POWER AMPLIFIER  
GFSK MODULATION  
The output stage is based on a Class E amplifier design, with an  
open drain output switched by the VCO signal. The output  
control consists of six current mirrors operating as a  
programmable current source.  
Gaussian Frequency Shift Keying, or GFSK, represents a filtered  
form of frequency shift keying. The data to be modulated to RF  
is prefiltered digitally using an finite impulse response filter  
(FIR). The filtered data is then used to modulate the sigma-  
delta fractional-N to generate spectrally-efficient FSK.  
To achieve maximum voltage swing, the RFOUT pin needs to be  
biased at DVDD. A single pull-up inductor to DVDD ensures a  
current supply to the output stage, PA biased to DVDD volts, and  
with the correct choice of value transforms the impedance.  
FSK consists of a series of sharp transitions in frequency as the  
data is switched from one level to an other. The sharp switching  
generates higher frequency components at the output, resulting  
in a wider output spectrum.  
The output power can be adjusted by changing the value of  
bits P1 to P6. Typically, this is P1 to P6 output −20dBm at 0x0,  
and 13 dBm at 0x7E at 868MHz, with the optimum matching  
network.  
With GFSK, the sharp transitions are replaced with up to 128  
smaller steps. The result is a gradual change in frequency. As a  
result, the higher frequency components are reduced and the  
spectrum occupied is reduced significantly. GFSK does require  
some additional design work as the data is only sampled once  
per bit, and so the choice of crystal is important to ensure the  
correct sampling clock is generated.  
Rev. 0 | Page 14 of 28  
 
 
ADF7012  
The nonlinear characteristic of the output stage results in an  
output spectrum containing harmonics of the fundamental,  
especially the third and fifth. To meet local regulations, a low-  
pass filter usually is required to filter these harmonics.  
As is the case with GFSK, GOOK requires the bit stream  
applied at TxDATA to be synchronized with the sampling clock,  
TxCLK (see the GFSK Modulation section).  
10  
The output stage can be powered down by setting Bit PD2 in  
the function register low.  
0
–10  
OOK  
GOOK MODULATION  
–20  
Gaussian on-off keying (GOOK) represents a prefiltered form  
of OOK modulation. The usually sharp symbol transitions are  
replaced with smooth Gaussian-filtered transitions with the  
result being a reduction in frequency pulling of the VCO.  
Frequency pulling of the VCO in OOK mode can lead to a  
wider than desired bandwidth, especially if it is not possible to  
increase the loop filter bandwidth to > 300kHz.  
–30  
–40  
–50  
–60  
GOOK  
–70  
–80  
909.43  
910.43  
910.93  
The GOOK sampling clock samples data at the data rate:  
FREQUENCY (MHz)  
FPFD  
Figure 33. GOOK vs. OOK Frequency Spectra  
(Narrow-Band Measurement)  
(9)  
DataRate(bps) =  
DividerFactor× IndexCounter  
20  
10  
0
Bits D1 to D6 represent the output power for the system for a  
positive data bit. Divider Factor = 0x3F represents the max-  
imum possible deviation from PA at minimum to PA at  
maximum output. An index counter setting of 128 is  
recommended.  
–10  
–20  
–30  
–40  
–50  
–60  
–70  
OOK  
Figure 32 shows the step response of the Gaussian FIR filter.  
An index counter of 16 is demonstrated for simplicity. While  
the pre-filter data would switch the PA directly from off to on  
with a low-to-high data transition, the filtered data gradually  
increases the PA output in discrete steps. This has the effect of  
making the output spectrum more compact.  
GOOK  
–80  
–90  
885.43  
910.43  
FREQUENCY (MHz)  
935.93  
PRE-FILTER DATA  
(0 TO 1 TRANSITION)  
PA SETTING  
16 (MAX)  
15  
14  
Figure 34. GOOK vs. OOK Frequency Spectra  
(Wideband Measurement)  
13  
12  
11  
10  
9
8
7
6
5
4
DISCRETIZED  
FILTER OUTPUT  
3
2
1 (PA OFF)  
Figure 32. Varying PA Output for GOOK (Index Counter = 16).  
Rev. 0 | Page 15 of 28  
 
 
ADF7012  
OUTPUT DIVIDER  
Battery Voltage Read back  
By setting MUXOUT to 1010 to 1101, the battery voltage can be  
estimated. The battery measuring circuit features a voltage  
divider and a comparator where the divided-down supply  
voltage is compared to the regulator voltage.  
An output divider is a programmable divider following the  
VCO in the PLL loop. It is useful when using the ADF7012 to  
generate frequencies of < 500 MHz.  
REFERENCE  
DIVIDER  
LOOP  
FILTER  
OUTPUT  
DIVIDER  
PFD  
CP  
PA  
VCO  
Table 6.  
÷1/2/4/8  
MUXOUT  
MUXOUT High  
DVDD > 3.25 V  
DVDD > 3.0 V  
MUXOUT Low  
DVDD < 3.25 V  
DVDD < 3.0 V  
÷N  
1010  
1011  
Figure 35. Output Divider Location in PLL.  
1100  
1101  
DVDD > 2.75 V  
DVDD > 2.35 V  
DVDD < 2.75 V  
DVDD < 2.35 V  
The output divider may be used to reduce feedthrough of the  
VCO by amplifying only the VCO/2 component, restricting the  
VCO feedthrough to leakage.  
The accuracy of the measurement is limited by the accuracy of  
the regulator voltage and also the internal resistor tolerances.  
Regulator Ready  
Because the divider is in loop, the N register values should be  
set up according to the usual formula. However, the VCO gain  
(KV) should be scaled according to the divider setting, as shown  
in the following example.  
The regulator has a power-up time, dependant on process and  
the external capacitor. The regulator ready signal indicates that  
the regulator is fully powered, and that the serial interface is  
active. This is the default setting on power-up at MUXOUT.  
Fout = 433 MHz, Fvco = 866 MHz, KV @ 868 MHz =  
60 MHz/V  
Digital Lock Detect  
Digital lock detect indicates that the status of the PLL loop.  
The PLL loop takes time to settle on power-up and when the  
frequency of the loop is changed by changing the N value.  
When lock detect is high, the PFD has counted a number of  
consecutive cycles where the phase error is < 15 ns. The lock  
detect precision bit in the function register determines whether  
this is 3 cycles (LDP = 0), or 5 cycles (LDP=1). It is recom-  
mended that LDP be set to 1. The lock detect is not completely  
accurate and goes high before the output has settled to exactly  
the correct frequency. In general, add 50ꢀ to the indicated  
lock time to obtain lock time to within 1 kHz. The lock detect  
signal can be used to decide when the power amplifier (PA)  
should be enabled.  
Therefore, KV for loop filter design = 30 MHz/V.  
The divider value is set in the R register.  
Table 5.  
OD1  
OD2  
Divider Status  
Divider off  
Divide by 2  
Divide by 4  
Divide by 8  
0
0
1
1
0
1
0
1
MUXOUT MODES  
The MUXOUT pin allows the user access to various internal  
signals in the transmitter, and provides information on the  
PLL lock status, the regulator, and the battery voltage. The  
MUXOUT is accessed by programming Bits M1 to M4 in the  
function register and observing the signal at the MUXOUT pin.  
R Divider  
MUXOUT provides the output of the R divider. This is a  
narrow pulsed digital signal at frequency FPFD. This signal may  
be used to check the operation of the crystal circuit and the R  
divider. R divider/2 is a buffered version of this signal at FPFD/2.  
Rev. 0 | Page 16 of 28  
 
ADF7012  
THEORY OF OPERATION  
CHOOSING THE EXTERNAL INDUCTOR VALUE  
Standard Crystal Values  
Standard crystal values are 3.6864 MHz, 4 MHz, 4.096 MHz,  
4.9152 MHz, 7.3728 MHz, 9.8304 MHz, 10 MHz, 11.0592 MHz,  
12 MHz, and 14.4792 MHz. Crystals with these values are  
usually available in stock and cost less than crystals with  
nonstandard values.  
The ADF7012 allows operation at many different frequencies by  
choosing the external VCO inductor to give the correct output  
frequency. Figure 36 shows both the minimum and maximum  
frequency vs. the inductor value. These are measurements based  
on 0603 CS type inductors from Coilcraft, and are intended as  
guidelines in choosing the inductor because board layout and  
inductor type varies between applications.  
Reference Spurious Levels  
Reference spurious levels (spurs) occur at multiples of the PFD  
frequency. The reference spur closest to the carrier is usually  
highest with the spur further out being attenuated by the loop  
filter. The level of reference spur is lower for lower PFD  
frequencies. In designs with high output power where spurious  
levels are the main concern, a lower PFD frequency (<5 MHz)  
may be desirable.  
The inductor value should be chosen so it is between the  
minimum and maximum value.  
1200  
MIN (meas)  
1100  
MAX (meas)  
MIN (eqn)  
1000  
MAX (eqn)  
Beat Note Spurs  
900  
These are spurs occurring for very small or very large values in  
the fractional register. These are quickly attenuated by the loop  
filter. Selection of the PFD therefore determines their location,  
and ensures that they have negligible effect on the transmitter  
spectrum.  
800  
700  
600  
500  
Phase Noise  
400  
300  
The phase noise of a frequency synthesizer improves by 3dB for  
every doubling of the PFD frequency. Because ACP is related to  
the phase noise, the PFD may be increased to reduce the ACP  
in the system. PFD frequencies of < 5MHz typically deliver  
sufficient phase noise performance for most systems.  
0
5
10  
15  
20  
25  
30  
35  
INDUCTANCE (nH)  
Figure 36. Output Frequency vs. External Inductor Value  
Ibias = 2.0 mA.  
For frequencies between 270 MHz and 550 MHz, it is  
Deviation Frequency  
recommended to operate the VCO at twice the desired output  
frequency and use the divide-by-2 option. This ensures reliable  
operation over temperature and supply.  
The deviation frequency is adjustable in steps of  
FPFD  
214  
FSTEP (Hz) =  
(10)  
For frequencies between 130 MHz and 270 MHz, it is  
recommended to operate the VCO at four times the desired  
output frequency and use the divide-by-4 option.  
To get the exact deviation frequency required, ensure FSTEP is a  
factor of the desired deviation.  
For frequencies below 130 MHz, it is best to use the divide-by-8  
option. It is not necessary to use the VCO divider for  
frequencies above 550 MHz.  
TIPS ON DESIGNING THE LOOP FILTER  
The loop filter design is crucial in ensuring stable operation of  
the transmitter, meeting Adjacent Channel Power (ACP)  
specifications, and meeting spurious requirements for the  
relevant regulations. ADIsimPLL is a free tool available to aid  
the design of loop filters. The user enters the desired frequency  
range, the reference crystal and PFD values, and the desired  
loop bandwidth. ADIsimPLL gives a good starting point for the  
filter, and the filter can be further optimized based on the  
criteria below.  
ADIsimPLL is a PLL design tool which can perform the  
frequency calculations for the ADF7012, and is available at  
www.analog.com/pll.  
CHOOSING THE CRYSTAL/PFD VALUE  
The choice of crystal value is an important one. The PFD  
frequency must be the same as the crystal value or an integer  
division of it. The PFD determines the phase noise, spurious  
levels and location, deviation frequency, and the data rate in the  
case of GFSK. The following sections describe some factors that  
should be considered when choosing the crystal value.  
Rev. 0 | Page 17 of 28  
 
 
ADF7012  
Setting Tuning Sensitivity Value  
PA MATCHING  
The ADF7012 exhibits optimum performance in terms of  
transmit power and current consumption only if the RF output  
port is properly matched to the antenna impedance.  
The tuning sensitivity or kV is usually denoted in MHz/V and is  
required for the loop filter design. It refers to the amount that a  
change of a volt in the voltage applied to VCOIN pin, changes  
the output frequency. Typical data for the ADF7012 over a  
frequency range is shown.  
ZOPT_PA depends primarily on the required output power,  
and the frequency range. Selecting the optimum ZOPT_PA  
helps to minimize the current consumption. This data sheet  
contains a number of matching networks for common  
frequency bands. Under certain conditions it is recommended  
to obtain a suitable ZOPT_PA value by means of a load-pull  
measurement.  
120  
100  
80  
60  
DV  
DD  
40  
RF  
OUT  
20  
0
PA  
ANTENNA  
LPF  
ZOPT_PA  
200  
300  
400  
500  
600  
700  
800  
900 1000 1100  
FREQUENCY (MHz)  
Figure 37. kV vs. VCO Frequency  
Figure 38. ADF7012 with Harmonic Filter  
Charge-Pump Current  
The impedance matching values provided in the next section  
are for 50 Ω environments. An additional matching network  
may be required after the harmonic filter to match to the  
antenna impedance. This can be incorporated into the filter  
design itself in order to reduce external components.  
The charge-pump current allows the loop filter bandwidth to be  
changed using the registers. The loop bandwidth reduces as the  
charge pump current is reduced and vice versa.  
Selecting Loop Filter Bandwidth  
Data Rate  
TRANSMIT PROTOCOL AND CODING  
CONSIDERATIONS  
The loop filter bandwidth should usually be at two to three  
times the data rate. This ensures that the PLL has ample time  
to jump between the mark and space frequencies.  
SYNC  
ID  
PREAMBLE  
WORD  
FIELD  
DATA FIELD  
CRC  
ACP  
Figure 39. Typical Format of a Transmit Protocol  
In the case where the ACP specifications are difficult to meet,  
the loop filter bandwidth can be reduced further to reduce the  
phase noise at the adjacent channel. The filter rolls off at 20 dB  
per decade.  
A dc-free preamble pattern such as 10101010… is recom-  
mended for FSK/ASK/OOK demodulation. Preamble patterns  
with longer run-length constraints such as 11001100…. can also  
be used. However, this can result in a longer synchronization  
time of the received bit stream in the chosen receiver.  
Spurious Levels  
In the case where the output power is quite high, a reduced loop  
filter bandwidth reduces the spurious levels even further, and  
provides additional margin on the specification.  
The following sections provide examples of loop filter designs  
for typical applications in specific frequencies.  
Rev. 0 | Page 18 of 28  
 
ADF7012  
APPLICATION EXAMPLES  
R2  
C1  
C2  
R1  
C3  
V
DD  
U1  
ADF7012  
C5  
2.2µF  
C5  
100pF  
C10  
470nF  
C5+  
10µF  
C11  
0.22µF  
C
REG2  
V
DD  
1
2
24  
DV  
DD  
C
REG2  
C
C6  
2.2µF  
REG1  
R9  
3.6kΩ  
23  
C
R
SET  
REG1  
3
4
22  
21  
CP  
OUT  
AGND  
C12  
100pF  
C13  
2.2µF  
V
J1  
DD  
TxDATA  
1kΩ  
TxDATA  
TxCLK  
TxDATA  
TxCLK  
DV  
DD  
L1  
J4  
1kΩ  
5
6
7
8
20  
19  
18  
17  
C14  
L2  
LF1  
CF1  
LF2  
RF  
TxCLK  
OUT  
C15  
1kΩ  
MUXOUT  
CF2  
CF2  
MUXOUT  
RF  
MUXOUT  
Y1  
GND  
DGND  
OSC1  
OSC2  
VCO  
IN  
C7  
27pF  
C8  
27pF  
OSC1  
OSC2  
C
VCO  
L2  
J2  
C9  
9
16  
15  
L3  
1k  
CLK  
OUT  
10  
CLK  
OUT  
CLK  
OUT  
L1  
CE  
LE  
R3  
CLK  
CLK  
1kΩ  
11  
12  
14  
13  
V
DD  
J3–3  
J3–5  
CLK  
R4  
DATA  
DATA  
LE  
1kΩ  
DATA  
CE  
R5  
LE  
1kΩ  
J3–7  
J3–6  
J3–8  
TxDATA  
J5–1  
J5–2  
J5–4  
J5–5  
J5–8  
TxCLK  
CLK  
MUXOUT  
CLK  
J5–3  
J5–5  
J5–7  
OUT  
R6  
1kΩ  
R7  
1kΩ  
R8  
1kΩ  
DATA  
CE  
LE  
V
J5–9 J5–10  
DD  
10 PIN HEADER (5X2)  
Figure 40. Applications Diagrams with Harmonic Filter  
Rev. 0 | Page 19 of 28  
 
ADF7012  
315 MHZ OPERATION  
Bias Current  
The recommendations here are guidelines only. The design  
should be subject to internal testing prior to FCC site testing.  
Matching components need to be adjusted for board layout.  
Because low current is desired, a 2.0 mA VCO bias can be used.  
Additional bias current reduces any spur, but increases current  
consumption.  
The FCC standard 15.231 regulates operation in the band  
from 260MHz to 470MHz in the US. This is used generally in  
the transmission of RF control signals, such as in a satellite-  
decoder remote control, or remote keyless entry system. The  
band cannot be used to send any continuous signal. The  
maximum output power allowed is governed by the duty cycle  
of the system. A typical design example for a remote control is  
shown next.  
The PA bias can be set to 5.5 mA and achieve 0 dBm.  
Loop Filter Bandwidth  
The loop filter is designed with ADIsimPLL Version 2.5. The  
loop bandwidth design is straightforward because the 20 dB  
bandwidth is generally of the order of >400 kHz (0.25ꢀ of  
center frequency). A loop bandwidth of close to 100 kHz strikes  
a good balance between lock time and spurious suppression. If  
it is found that pulling of the VCO is more than desired in OOK  
mode, the bandwidth could be increased.  
Design Criteria  
315 MHz center frequency  
FSK/OOK modulation  
1 mW output power  
House range  
Design of Harmonic Filter  
The main requirement of the harmonic filter should ensure that  
the third harmonic level is < −41.5 dBm. A fifth-order  
Chebyshev filter is recommended to achieve this, and a  
suggested starting point is given next. The Pi format is chosen  
to minimize the more expensive inductors.  
Meets FCC 15.231  
The main requirements in the design of this remote are a long  
battery life and sufficient range. It is possible to adjust the  
output power of the ADF7012 to increase the range depending  
on the antenna performance.  
Component Values—Crystal: 3.6864MHz  
Loop Filter  
ICP  
0.866 mA  
100 kHz  
680 pF  
12 nF  
220 pF  
1.1 kV  
3 kV  
The center frequency is 315 MHz. Because the ADF7012  
VCO is not recommended for operation in fundamental mode  
for frequencies below 400 MHz, the VCO needs to operate at  
630 MHz. Figure 36 (Output Frequency vs. External Inductor  
Value) implies an inductor value of 7.6 nH or close to this. The  
chip inductor chosen = 7.5 nH (0402CS-7N5 from Coilcraft).  
Coil inductors are recommended to provide sufficient Q for  
oscillation.  
LBW  
C1  
C2  
C3  
R1  
R2  
Matching  
L1  
L2  
C14  
C15  
56 nH  
1 nF  
Short  
Crystal and PFD  
Phase noise requirements are not excessive as the adjacent  
channel power requirement is −20 dB. The PFD is chosen so as  
to minimize spurious levels (beat note and reference), and to  
ensure a quick crystal power-up time.  
Open  
Harmonic Filter  
L4  
L5  
CF1  
CF2  
CF3  
22 nH  
22 nH  
3.3 pF  
8.2 pF  
3.3 pF  
PFD = 3.6864 MHz − Power-Up Time 1.6ms. Figure 10 shows a  
typical power-on time for a 4 MHz crystal.  
N-Divider  
The N Divider is determined as being:  
Nint = 85  
Nfrac = (1850)/4096  
VCO divide-by-2 is enabled  
Deviation  
The deviation is set to 50 kHz so as to accommodate a simple  
receiver architecture.  
The modulation steps available are in 3.6864 MHz/214 :  
Modulation steps = 225 Hz  
Modulation number = 50 kHz/225 Hz = 222  
Rev. 0 | Page 20 of 28  
 
ADF7012  
433 MHZ OPERATION  
Loop Filter Bandwidth  
The recommendations here are guidelines only. The design  
should be subject to internal testing prior to ETSI site testing.  
Matching components need to be adjusted for board layout.  
The loop filter is designed with ADIsimPLL Version 2.5. The  
loop bandwidth design requires that the channel power be  
< −36 dBm at 870 kHz from the center. A loop bandwidth of  
close to 160 kHz strikes a good balance between lock time for  
data rates, including 32 kbps and spurious suppression. If it is  
found that pulling of the VCO is more than desired in OOK  
mode, the bandwidth could be increased.  
The ETSI standard EN 300-220 governs operation in the  
433.050 MHz to 434.790 MHz band. For many systems, 10ꢀ  
duty is sufficient for the transmitter to output 10 dBm.  
Design Criteria  
433.92 MHz center frequency  
FSK modulation  
10 mW output power  
200 m range  
Design of Harmonic Filter  
The main requirement of the harmonic filter should ensure  
that the third harmonic level is < −30 dBm. A fifth-order  
Chebyshev filter is recommended to achieve this, and a  
suggested starting point is given next. The Pi format is chosen  
to minimize the more expensive inductors.  
Meets ETSI 300-220  
The main requirement in the design of this remote is a long  
battery life and sufficient range. It is possible to adjust the  
output power of the ADF7012 to increase the range depending  
on the antenna performance.  
Component Values—Crystal: 4.9152 MHz  
Loop Filter  
Icp  
LBW  
C1  
2.0 mA  
100 kHz  
680 pF  
12 nF  
The center frequency is 433.92 MHz. It is possible to operate the  
VCO at this frequency. Figure 36 shows the inductor value vs.  
center frequency. The inductor chosen is 22 nH. Coilcraft  
inductors such as 0603-CS-22NXJBU are recommended.  
C2  
C3  
270 pF  
R1  
R2  
910 V  
3.3 kV  
Crystal and PFD  
The phase noise requirement is such to ensure the power at the  
edge of the band is < −36 dBm. The PFD is chosen so as to  
minimize spurious levels (beat note and reference), and to  
ensure a quick crystal power-up time.  
Matching  
L1  
22 nH  
L2  
C14  
C15  
10 pF  
Short  
Open  
PFD = 4.9152 MHz − Power-Up Time 1.6 ms. Figure 10 shows a  
typical power-up time for a 4 MHz crystal.  
Harmonic Filter  
N-Divider  
L4  
L5  
CF1  
CF2  
CF3  
22 nH  
22 nH  
3.3 pF  
8.2 pF  
3.3 pF  
The N Divider is determined as being:  
Nint = 88  
Nfrac = (1152)/4096  
VCO divide-by-2 is not enabled  
Deviation  
The deviation is set to 50 kHz so as to accommodate a simple  
receiver architecture.  
The modulation steps available are in 4.9152 MHz/214 :  
Modulation steps = 300 Hz  
Modulation number = 50 kHz/300Hz = 167  
Bias Current  
Because low current is desired, a 2.0 mA VCO bias can be used.  
Additional bias current reduces any spurious, but increases  
current consumption.  
The PA bias can be set to 5.5 mA and achieve 10 dBm.  
Rev. 0 | Page 21 of 28  
 
ADF7012  
868 MHZ OPERATION  
The recommendations here are guidelines only. The design  
should be subject to internal testing prior to ETSI site testing.  
Matching components need to be adjusted for board layout.  
The modulation steps available are in 4.9152 MHz/214 :  
Modulation steps = 300 Hz  
Modulation number = 19.2 kHz/300 Hz = 64.  
Bias Current  
The ETSI standard EN 300-220 governs operation in the  
868 MHz to 870MHz band. The band is broken down into  
several subbands each having a different duty cycle and output  
power requirement. Narrowband operation is possible in the  
50kHz channels, but both the output power and data rate are  
limited by the −36 dBm adjacent channel power specification.  
There are many different applications in this band, including  
remote controls for security, sensor interrogation, metering  
and home control.  
Because low current is desired, a 2.5 mA VCO bias can be used.  
Additional bias current reduces any spurious, but increases  
current consumption. A 2.5 mA bias current gives the best  
spurious vs. phase noise trade-off.  
The PA bias should be set to 7.5 mA to achieve 12 dBm.  
Loop Filter Bandwidth  
The loop filter is designed with ADIsimPLL Version 2.5. The  
loop bandwidth design requires that the channel power be  
< −36 dBm at 250 kHz from the center. A loop bandwidth of  
close to <60 kHz is required to bring the phase noise at the edge  
of the band sufficiently low to meet the ACP specification. This  
represents a compromise between the data rate requirement and  
the phase noise requirement.  
Design Criteria  
868.95 MHz center frequency (band 868.7MHz − 869.2 MHz)  
FSK modulation  
12 dBm output power  
300 m range  
Meets ETSI 300-220  
38.4 kbps data rate  
Design of Harmonic Filter  
The main requirement of the harmonic filter should ensure that  
the second and third harmonic levels are < −30 dBm. A fifth-  
order Chebyshev filter is recommended to achieve this, and a  
suggested starting point is given next. The Pi format is chosen  
to minimize the more expensive inductors.  
The design challenge is to enable the part to operate in this  
particular subband and meet the ACP requirement 250 kHz  
away from the center.  
The center frequency is 868.95 MHz. It is possible to operate the  
VCO at this frequency. Figure 31 shows the inductor value vs.  
center frequency. The inductor chosen is 1.9 nH. Coilcraft  
inductors such as 0402-CS-1N9XJBU are recommended.  
Component Values—Crystal: 4.9152 MHz  
Loop Filter  
Icp  
LBW  
C1  
1.44 mA  
60 kHz  
1.5 nF  
22 nF  
Crystal and PFD  
The phase noise requirement is such to ensure the power at  
the edge of the band is < −36 dBm. This requires close to  
−100 dBc/Hz phase noise at the edge of the band.  
C2  
C3  
560 pF  
R1  
390 V  
The PFD is chosen so as to minimize spurious levels (beat note  
and reference), and to ensure a quick crystal power-up time. A  
PFD of < 6 MHz places the largest PFD spur at a frequency of  
greater than 862 MHz, and so reduces the requirement on the  
spur level to −36 dBm instead of −54 dBm.  
R2  
910 V  
Matching  
L1  
L2  
C14  
27 nH  
6.2 nH  
470 pF  
Open  
PFD = 4.9152 MHz − Power Up-Time 1.6 ms. Figure 10 shows a  
typical power-on time for a 4MHz crystal.  
C15  
Harmonic Filter  
L4  
L5  
CF1  
CF2  
CF3  
N-Divider  
8.2 nH  
8.2 nH  
4.7 pF  
6.8 pF  
4.7 pF  
The N divider is determined as being:  
Nint = 176  
Nfrac = (3229)/4096  
VCO divide-by-2 is not enabled.  
Deviation  
The deviation is set to 19.2 kHz so as to accommodate a  
simple receiver architecture and also ensure that the  
modulation spectrum is narrow enough to meet the adjacent  
channel power (ACP) requirements.  
Rev. 0 | Page 22 of 28  
 
ADF7012  
915 MHZ OPERATION  
Deviation  
The recommendations here are guidelines only. The design  
should be subject to internal testing prior to FCC site testing.  
Matching components need to be adjusted for board layout.  
The deviation is set to 19.2 kHz so as to accommodate a  
simple receiver architecture, and also to ensure the available  
spectrum is used efficiently.  
FCC 15.247 and FCC 15.249 are the main regulations governing  
operation in the 902 MHz to 928 MHz Band. FCC 15.247  
requires some form of spectral spreading. Typically, the  
ADF7012 would be used in conjunction with the frequency  
hopping spread spectrum (FHSS) or it may be used in  
conjunction with the digital modulation standard which  
requires large deviation frequencies. Output power of < 1 W  
is tolerated on certain spreading conditions.  
The modulation steps available are in 10 MHz/214 :  
Modulation steps = 610 Hz  
Modulation number = 19.2 kHz/610 Hz = 31.  
Bias Current  
Because low current is desired, a 3 mA VCO bias can be used  
and still ensure oscillation at 928 MHz. Additional bias current  
reduces any spurious noise, but increases current consumption.  
A 3 mA bias current gives the best spurious vs. phase noise  
trade-off.  
Compliance with FCC 15.249 limits the output power to  
−1.5 dBm, but does not require spreading. There are many  
different applications in this band, including remote controls  
for security, sensor interrogation, metering, and home control.  
The PA bias should be set to 5.5 mA to achieve 10 dBm power.  
Loop Filter Bandwidth  
Design Criteria  
915.2MHz center frequency  
FSK modulation  
10 dBm output power  
200 m range  
The loop filter is designed with ADIsimPLL Version 2.5. A  
data rate of 170 kHz is chosen, which allows for data rates of  
> 38.4 kbps. It also attenuates the beat note spurs quickly to  
ensure they have no effect on system performance.  
Meets FCC 15.247  
38.4 kbps data rate  
Design of Harmonic Filter  
The main requirement of the harmonic filter should ensure  
that the third harmonic level is < −41.5 dBm. A fifth-order  
Chebyshev filter is recommended to achieve this, and a  
suggested starting point is given next. The Pi format is chosen  
to minimize the number of inductors in the system.  
The center frequency is 915.2 MHz. It is possible to operate  
the VCO at this frequency. Figure 36 shows the inductor value  
vs. center frequency. The inductor chosen is 1.6 nH. Coilcraft  
inductors such as 0603-CS-1N6XJBU are recommended.  
Additional hopping frequencies can easily be generated by  
changing the N value.  
Component Values—Crystal: 10 MHz  
Loop Filter  
Crystal and PFD  
Icp  
LBW  
C1  
1.44 mA  
170 kHz  
470 pF  
12 nF  
The phase noise requirement is such to ensure that the 20 dB  
bandwidth requirements are met. These are dependant on the  
channel spacing chosen. A typical channel spacing would be  
400 kHz, which would allow 50 channels in 20 MHz and enable  
the design to avoid the edges of the band.  
C2  
C3  
R1  
120 pF  
470 V  
R2  
1.8 kV  
The PFD is chosen so as to minimize spurious levels. There are  
beat note spurious levels at 910 MHz and 920 MHz, but the  
level is usually significantly less than the modulation power.  
They are also attenuated quickly by the loop filter to ensure a  
quick crystal power-up time.  
Matching  
L1  
L2  
C14  
C15  
27 nH  
6.2 nH  
470 pF  
Open  
PFD = 10 MHz − Power-Up Time 1.8 ms (approximately).  
Figure 10 shows a typical power-on time for a 4 MHz crystal.  
Harmonic Filter  
L4  
L5  
CF1  
CF2  
CF3  
8.2 nH  
8.2 nH  
4.7 pF  
6.8 pF  
4.7 pF  
N-Divider  
The N divider is determined as being:  
Nint = 91  
Nfrac = (2130)/4096  
VCO divide-by-2 is not enabled  
Rev. 0 | Page 23 of 28  
 
ADF7012  
REGISTER DESCRIPTIONS  
R REGISTER  
OUTPUT  
DIVIDER ADJUST  
VCO  
CLOCK OUT  
DIVIDER  
4-BIT R DIVIDER  
11-BIT FREQUENCY ERROR CORRECTION  
F-COUNTER  
OFFSET  
D1 CRYSTAL DOUBLER  
F11 ....... F3  
F2  
F1  
0
1
CRYSTAL DOUBLER OFF  
CRYSTAL DOUBLER ON  
+1023  
+1022  
.
+1  
+0  
0
0
0
0
0
.......  
.......  
.......  
.......  
.......  
1
1
.
0
0
0
0
.
0
0
0
1
.
1
0
X1 XOEB  
OD2 OD1  
OUTPUT DIVIDER  
0
1
XTAL OSCILLATOR ON (DEFAULT)  
XTAL OSCILLATOR OFF  
–1  
–0  
–1  
–1023  
–1024  
1
1
.
1
1
.......  
.......  
.......  
.......  
.......  
1
1
.
0
0
1
1
.
0
0
1
0
.
1
0
0
0
1
1
0
1
0
1
DISABLED  
DIVIDE BY 2  
DIVIDE BY 4  
DIVIDE BY 8  
e.g., F-COUNTER OFFSET = 1, FRACTIONAL  
15  
OFFSET = 1/2  
VA2 VA1  
VCO ADJUST  
NO VCO ADJUSTMENT  
0
0
1
1
0
1
0
1
(F  
(F  
(F  
– (1 × f))  
– (2 × f))  
– (3 × f))  
CENTER  
CENTER  
CENTER  
RF R COUNTER  
RL4  
RL3  
RL2  
RL1  
DIVIDE RATIO  
1
0
0
0
0
.
0
0
0
1
.
0
1
1
0
.
1
0
1
0
.
2
3
4
.
CLK  
OUT  
CL4  
CL3  
CL2  
CL1  
DIVIDE RATIO  
2
0
0
0
0
.
0
0
0
1
.
0
1
1
0
.
1
0
1
0
.
4
.
.
.
.
.
.
6
.
.
.
.
8
12  
13  
14  
15  
1
1
1
1
1
1
1
1
0
0
1
1
0
1
0
1
.
.
.
.
.
16 (DEFAULT)  
.
.
.
.
.
28  
1
1
1
1
1
1
0
1
30  
Figure 41.  
Rev. 0 | Page 24 of 28  
 
ADF7012  
N-COUNTER LATCH  
8-BIT INTEGER-N  
12-BIT FRACTIONAL-N  
MODULUS  
DIVIDE RATIO  
M12 M11  
M10 ....... M3  
M2  
M1  
0
1
2
.
.
.
4092  
4093  
4094  
4095  
0
0
0
.
.
.
1
1
1
1
0
0
0
.
.
.
1
1
1
1
0
0
0
.
.
.
1
1
1
1
.......  
.......  
.......  
.......  
.......  
.......  
.......  
.......  
.......  
.......  
0
0
0
.
.
.
1
1
1
1
0
0
1
.
.
.
0
0
1
1
0
1
0
.
.
.
0
1
0
1
e.g., SETTING F = 0 IN FSK MODE TURNS ON THE Σ-WHILE  
THE PLL IS AN INTEGER VALUE  
N-COUNTER  
N8  
0
0
0
.
N7  
0
0
0
.
N6  
0
0
0
.
N5  
0
0
0
.
N4  
0
0
0
.
N3  
0
0
0
.
N2  
0
0
1
.
N1  
0
1
0
.
DIVIDE RATIO  
1
2
3
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
254  
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
1
255  
e.g., MODULUS DIVIDE RATIO = 2048 - > 1/2  
P1 PRESCALER  
THE N-VALUE CHOSEN IS A MINIMUM OF  
2
P
+ 3P + 3. FOR PRESCALER 8/9 THIS  
0
1
4/5  
8/9  
MEANS A MINIMUM N-DIVIDE OF 91.  
Figure 42.  
Rev. 0 | Page 25 of 28  
 
ADF7012  
MODULATION REGISTER  
GFSK MOD  
CONTROL  
TEST BITS  
MODULATION DEVIATION  
POWER AMPLIFIER  
MUST BE LOW  
G1 GAUSSIAN OOK  
ON  
OFF  
0
1
MODULATION  
SCHEME  
S2  
S1  
0
0
1
1
0
1
0
1
FSK  
GFSK  
ASK  
OOK  
IF AMPLITUDE SHIFT KEYING SELECTED, TxDATA = 0  
POWER AMPLIFIER OUTPUT LEVEL  
D6  
0
.
.
.
D2  
X
0
0
1
.
D1  
X
0
1
0
.
P6  
0
0
0
0
.
.
.
P2  
X
0
1
1
.
P1  
X
1
0
1
.
PA OFF  
PA OFF  
.
.
.
.
.
.
–16.0dBm  
1/31 * 14dBm  
2/31 * 14dBm  
.
.
.
–16.0dBm  
1/31 * 14dBm  
2/31 * 14dBm  
.
0
0
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
14dBm  
13dBm  
1
1
1
1
1
1
1
1
1
1
IF FREQUENCY SHIFT KEYING SELECTED  
14  
/2  
STEP = PFD  
F
F
D9  
0
....... D3  
D2  
0
D1  
0
1
0
1
.
F DEVIATION  
PLL MODE  
.......  
.......  
.......  
.......  
.......  
.......  
0
0
0
0
.
0
0
1 × –F  
2 × –F  
3 × –F  
.......  
STEP  
STEP  
STEP  
0
1
0
1
.
.
1
1
1
.
511 × –F  
STEP  
IF GAUSSIAN FREQUENCY SHIFT KEYING SELECTED  
IC2  
0
IC1  
0
INDEX COUNTER  
D7  
0
.......  
.......  
.......  
.......  
.......  
.......  
.......  
D3  
0
D2  
0
D1  
0
DIVIDER FACTOR  
16  
0
0
1
32  
0
0
0
1
1
1
0
64  
0
0
1
0
2
1
1
128  
0
0
1
1
3
.
.
.
.
.......  
127  
MC3 MC2 MC1 GFSK MOD CONTROL  
1...  
1
1
1
0
0
.
0
0
.
0
1
.
0
1
.
1
1
1
7
Figure 43.  
Rev. 0 | Page 26 of 28  
 
ADF7012  
FUNCTION REGISTER  
SD TEST  
MODES  
PLL TEST  
MODES  
PA BIAS  
VCO BIAS  
MUXOUT  
BLEED CHARGE  
CURRENT PUMP  
I1 DATA INVERT  
0
1
DATA  
DATA  
CP4 BLEED DOWN  
PD1 PLL ENABLE  
PA3 PA2 PA1 PA BIAS  
5µA  
0
0
0
.
0
0
1
.
0
1
0
.
0
1
BLEED OFF  
BLEED ON  
0
1
PLL OFF  
PLL ON  
6µA  
7µA  
.
CP3 BLEED UP  
PD2 PA ENABLE  
.
.
.
.
0
1
BLEED OFF  
BLEED ON  
0
1
PAOFF  
PAON  
1
1
1
12µA  
CHARGE PUMP  
CURRENT  
CP2 CP1  
0
0
1
1
0
1
0
1
0.3mA  
0.9mA  
1.5mA  
2.1mA  
PD3 CLK  
OUT  
VD1 VCO DISABLE  
VCO BIAS  
VB4 VB3 VB2 VB1 CURRENT  
0
1
VCO ON  
VCO OFF  
0
CLK  
CLK  
OFF  
ON  
OUT  
OUT  
0.5mA  
0
0
.
0
0
.
0
1
.
1
0
.
1
1mA  
.
1
1
1
1
8mA  
M4  
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
M3  
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
M2  
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
M1  
MUXOUT  
LOGIC LOW  
LOGIC HIGH  
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
INVALID MODE – DO NOT USE  
REGULATOR READY (DEFAULT)  
DIGITAL LOCK DETECT  
ANALOG LOCK DETECT  
R DIVIDER/2 OUTPUT  
N DIVIDER/2 OUTPUT  
RF R DIVIDER OUTPUT  
DATA RATE  
BATTERY MEASURE IS > 3.25V  
BATTERY MEASURE IS > 3V  
BATTERY MEASURE IS > 2.75V  
BATTERY MEASURE IS > 2.35V  
NORMAL TEST MODES  
Σ-TEST MODES  
Figure 44.  
Rev. 0 | Page 27 of 28  
 
ADF7012  
OUTLINE DIMENSIONS  
7.90  
7.80  
7.70  
24  
13  
12  
4.50  
4.40  
4.30  
6.40 BSC  
1
PIN 1  
0.65  
BSC  
1.20  
MAX  
0.15  
0.05  
0.75  
0.60  
0.45  
8°  
0°  
0.30  
0.19  
0.20  
0.09  
SEATING  
PLANE  
0.10 COPLANARITY  
COMPLIANT TO JEDEC STANDARDS MO-153AD  
Figure 45. 24-Lead Thin Shrink Small Outline Package [TSSOP]  
(RU-24)  
ORDERING GUIDE  
Model  
Temperature Range  
Package Description  
Package Option  
Frequency Range  
ADF7012BRU  
TSSOP  
RU-24  
RU-24  
RU-24  
50 MHz to 1 GHz  
40°C to +85°C  
40°C to +85°C  
40°C to +85°C  
ADF7012BRU-REEL  
ADF7012BRU-REEL7  
EVAL-ADF7012EB1  
EVAL-ADF7012EB2  
EVAL-ADF7012EB3  
EVAL-ADF7012EB4  
EVAL-ADF7012EB5  
TSSOP, 13”REEL  
TSSOP, 7” REEL  
Evaluation Board  
Evaluation Board  
Evaluation Board  
Evaluation Board  
Evaluation Board  
50 MHz to 1 GHz  
50 MHz to 1 GHz  
902 MHz to 928 MHz  
860 MHz to 880 MHz  
418 MHz to 435 MHz  
310 MHz to 330 MHz  
50 MHz to 1 GHz  
©
2004 Analog Devices, Inc. All rights reserved. Trademarks and  
registered trademarks are the property of their respective owners.  
D04617–0–10/04(0)  
Rev. 0 | Page 28 of 28  
 

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