MAX1479ATE+ [MAXIM]
300MHz to 450MHz Low-Power, Crystal-Based +10dBm ASK/FSK Transmitter; 300MHz至450MHz，低功耗，基于晶体的+ 10dBm的ASK / FSK发射器
| 型号： | MAX1479ATE+ |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | 300MHz to 450MHz Low-Power, Crystal-Based +10dBm ASK/FSK Transmitter |
| 文件： | 总10页 (文件大小：126K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-3353; Rev 1; 6/09
300MHz to 450MHz Low-Power,
Crystal-Based +10dBm ASK/FSK Transmitter
MAX1479
General Description
Features
The MAX1479 crystal-referenced phase-locked-loop
(PLL) VHF/UHF transmitter is designed to transmit ASK,
OOK, and FSK data in the 300MHz to 450MHz frequency
range. The MAX1479 supports data rates up to 100kbps
in ASK mode and 20kbps in FSK mode (both
Manchester coded). The device provides an adjustable
output power of more than +10dBm into a 50Ω load. The
crystal-based architecture of the MAX1479 eliminates
many of the common problems of SAW-based transmit-
ters by providing greater modulation depth, faster fre-
quency settling, higher tolerance of the transmit
frequency, and reduced temperature dependence.
These improvements enable better overall receiver per-
formance when using the MAX1479 together with a
superheterodyne receiver such as the MAX1470,
MAX1471, MAX1473, or MAX7033.
o ETSI-Compliant EN300 220
o +2.1V to +3.6V Single-Supply Operation
o Supports ASK, OOK, and FSK Modulations
o Adjustable FSK Shift
o +10dBm Output Power into 50Ω Load
o Low Supply Current (6.7mA in ASK Mode,
and 10.5mA in FSK Mode)
o Uses Small Low-Cost Crystal
o Small 16-Pin TQFN Package
o Fast-On Oscillator—200µs Startup Time
o Programmable Clock Output
The MAX1479 is available in a 16-pin TQFN package
(3mm x 3mm) and is specified for the automotive tem-
perature range from -40°C to +125°C.
Ordering Information
Applications
Remote Keyless Entry
Tire Pressure Monitoring
Security Systems
PART
TEMP RANGE
PIN-PACKAGE
MAX1479ATE+
-40°C to +125°C
16 TQFN-EP*
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
Radio-Controlled Toys
Wireless Game Consoles
Wireless Computer Peripherals
Wireless Sensors
Typical Application Circuit appears at end of data sheet.
RF Remote Controls
Garage Door Openers
Functional Diagram
Pin Configuration
TOP VIEW
16
15
14
13
16 15 14 13
CRYSTAL
DRIVER
V
1
2
3
4
DEVIATION
12
11
DEV1
DEV0
DD
V
1
2
3
4
12 DEV1
11 DEV0
10 CLK1
DD
LOOP
FILTER
PD/CP
MODE
DIN
MODE
MAX1479
EP*
ASK
FSK
DIVIDE
BY 32
VCO
PA
ENABLE
9
CLK0
10 CLK1
DIN
5
6
7
8
MAX1479
CLOCK
DIVIDER
ENVELOPE
SHAPING
9
ENABLE
CLK0
5
6
7
8
TQFN
(3mm x 3mm)
*CONNECT EP TO GND.
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
300MHz to 450MHz Low-Power,
Crystal-Based +10dBm ASK/FSK Transmitter
ABSOLUTE MAXIMUM RATINGS
DD
All Other Pins to GND ................................-0.3V to (V
V
to GND .............................................................-0.3V to +4V
Operating Temperature Range .........................-40°C to +125°C
Junction Temperature......................................................+150°C
Storage Temperature Range.............................-60°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
+ 0.3V)
DD
Continuous Power Dissipation (T = +70°C)
A
16-Pin TQFN (derate 14.7mW/°C above +70°C).........1176.5mW
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
MAX1479
DC ELECTRICAL CHARACTERISTICS
(Typical Application Circuit, all RF inputs and outputs are referenced to 50Ω, V
= +2.1V to +3.6V, V
= +2.7V, T = +25°C, unless otherwise noted.) (Note 1)
= V , T = -40°C to
DD
ENABLE DD A
+125°C, unless otherwise noted. Typical values are at V
DD
A
PARAMETER
Supply Voltage
SYMBOL
V
CONDITIONS
MIN
TYP
MAX
UNITS
2.1
3.6
V
DD
PA off, V
at
DIN
f
RF
f
RF
f
RF
f
RF
= 315MHz
= 433MHz
= 315MHz
= 433MHz
2.9
3.3
6.7
7.3
4.3
4.8
0% duty cycle
(ASK or FSK)
(Note 2)
10.7
11.4
Supply Current
I
mA
DD
V
at 50% duty
DIN
cycle (ASK)
(Notes 3, 4)
f
f
= 315MHz (Note 2)
= 433MHz (Note 4)
= +25°C
10.5
11.4
0.2
17.1
18.1
RF
V
at 100%
DIN
duty cycle (FSK)
RF
T
T
T
A
A
A
Standby Current
I
V
< V
IL
nA
V
< +85°C (Note 4)
< +125°C (Note 2)
120
700
300
STDBY
ENABLE
1600
DIGITAL INPUTS AND OUTPUTS
V
0.25
-
DD
Data Input High
V
(Note 2)
(Note 2)
IH
Data Input Low
V
0.25
0.25
V
IL
Maximum Input Current
I
20
µA
IN
V
0.25
-
DD
Output Voltage High
Output Voltage Low
V
CLKOUT, load = 10kΩ || 10pF (Note 4)
CLKOUT, load = 10kΩ || 10pF (Note 4)
V
V
OH
V
OL
2
_______________________________________________________________________________________
300MHz to 450MHz Low-Power,
Crystal-Based +10dBm ASK/FSK Transmitter
MAX1479
AC ELECTRICAL CHARACTERISTICS
(Typical Application Circuit, all RF inputs and outputs are referenced to 50Ω, V
= +2.1V to +3.6V, V
= +2.7V, T = +25°C, unless otherwise noted.) (Note 1)
= V , T = -40°C to
DD
ENABLE DD A
+125°C, unless otherwise noted. Typical values are at V
DD
A
PARAMETER
SYSTEM PERFORMANCE
Frequency Range
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
f
(Note 2)
300
450
MHz
µs
RF
Settle to within 50kHz
200
350
100
20
Turn-On Time (Note 5)
t
ON
Settle to within 5kHz
ASK mode (Manchester coded)
FSK mode (Manchester coded)
Maximum Data Rate (Note 4)
kbps
kHz
f
RF
f
RF
= 315MHz
= 433MHz
55
Maximum FSK Frequency
Deviation
DEV[2:0] = 111
(Note 6)
80
T
T
T
= +25°C, V
= +2.7V
DD
6.8
2.7
10
12.0
16.1
A
Output Power (Note 2)
P
= +125°C, V
= +2.1V
DD
5.3
12.2
35
dBm
OUT
A
= -40°C, V
= +3.6V
A
DD
f
RF
f
RF
f
RF
f
RF
= 315MHz
= 433MHz
= 315MHz
= 433MHz
Transmit Efficiency with CW Tone
(Note 7)
%
%
34
27
Transmit Efficiency at 50% Duty
Cycle
25
PHASE-LOCKED-LOOP PERFORMANCE
VCO Gain
K
280
-75
-98
-74
-98
-50
-45
-40
300
MHz/V
VCO
f
f
f
f
= 100kHz
= 1MHz
OFFSET
OFFSET
OFFSET
OFFSET
f
f
= 315MHz
= 433MHz
RF
Phase Noise
dBc/Hz
= 100kHz
= 1MHz
RF
f
f
= 315MHz
= 433MHz
RF
Maximum Carrier Harmonics
dBc
RF
Reference Spur
dBc
kHz
MHz
ppm
pF
Loop Bandwidth
BW
Crystal Frequency Range
Crystal Tolerance
f
F
/ 32
XTAL
RF
50
Crystal Load Capacitance
Clock Output Frequency
C
(Note 8)
Determined by CLK0 and CLK1; see Table 1
4.5
LOAD
F
/N
MHz
XTAL
Note 1: Supply current, output power, and efficiency are greatly dependent on board layout and PAOUT match.
Note 2: 100% tested at T = +125°C. Guaranteed by design and characterization over temperature.
A
Note 3: 50% duty cycle at 10kHz ASK data (Manchester coded).
Note 4: Guaranteed by design and characterization, not production tested.
Note 5: V
= V to V
= V . f
is defined as the frequency deviation from the desired carrier frequency.
ENABLE
IL
ENABLE
IH OFFSET
Note 6: Dependent on crystal and PCB trace capacitance.
Note 7: V > V , V > V , Efficiency = P /(V
x I ).
DD
ENABLE
IH DATA
IH
OUT DD
Note 8: Dependent on PCB trace capacitance.
_______________________________________________________________________________________
3
300MHz to 450MHz Low-Power,
Crystal-Based +10dBm ASK/FSK Transmitter
Typical Operating Characteristics
(Typical Application Circuit, V
= +2.7V, T = +25°C, unless otherwise noted.)
A
DD
SUPPLY CURRENT vs. SUPPLY VOLTAGE
SUPPLY CURRENT vs. SUPPLY VOLTAGE
SUPPLY CURRENT vs. SUPPLY VOLTAGE
15
14
13
12
11
10
9
10.0
9.5
9.0
8.5
8.0
7.5
7.0
6.5
6.0
5.5
5.0
15
14
13
12
11
10
9
f
= 315MHz
f
= 315MHz
f
= 433MHz
RF
RF
RF
PA ON
PA 50% DUTY CYCLE AT 10kHz
PA ON
TA = -40°C
TA = -40°C
MAX1479
TA = +85°C
TA = +25°C
TA = +25°C
TA = +125°C
TA = +85°C
TA = +125°C
TA = +85°C
TA = +125°C
TA = +25°C
TA = -40°C
8
8
7
7
2.1
2.4
2.7
3.0
3.3
3.6
2.1
2.4
2.7
3.0
3.3
3.6
2.1
2.4
2.7
3.0
3.3
3.6
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
SUPPLY CURRENT vs. SUPPLY VOLTAGE
SUPPLY CURRENT vs. OUTPUT POWER
SUPPLY CURRENT vs. OUTPUT POWER
10.0
9.5
9.0
8.5
8.0
7.5
7.0
6.5
6.0
5.5
5.0
12
11
10
9
12
11
10
9
f
= 433MHz
RF
f
= 315MHz
f
= 433MHz
RF
RF
PA 50% DUTY CYCLE AT 10kHz
TA = +85°C
PA ON
PA ON
8
8
TA = +125°C
7
7
TA = +25°C
6
6
5
5
TA = -40°C
50% DUTY CYCLE
4
50% DUTY CYCLE
4
3
3
2
2
2.1
2.4
2.7
3.0
3.3
3.6
-14
-10
-6
-2
2
6
10
-14
-10
-6
-2
2
6
10
SUPPLY VOLTAGE (V)
AVERAGE OUTPUT POWER (dBm)
AVERAGE OUTPUT POWER (dBm)
SUPPLY CURRENT AND OUTPUT POWER
SUPPLY CURRENT AND OUTPUT POWER
vs. EXTERNAL RESISTOR
vs. EXTERNAL RESISTOR
MAX1479 toc07
MAX1479 toc08
18
16
14
12
10
8
16
18
16
14
12
10
8
16
12
8
f
= 315MHz
f
= 433MHz
RF
RF
12
8
PA ON
PA ON
POWER
POWER
4
4
0
0
CURRENT
-4
-8
-12
-16
-4
-8
-12
-16
CURRENT
6
6
4
4
2
2
0.1
1
10
100
1k
10k
0.1
1
10
100
1k
10k
EXTERNAL RESISTOR (Ω)
EXTERNAL RESISTOR (Ω)
4
_______________________________________________________________________________________
300MHz to 450MHz Low-Power,
Crystal-Based +10dBm ASK/FSK Transmitter
MAX1479
Typical Operating Characteristics (continued)
(Typical Application Circuit, V
= +2.7V, T = +25°C, unless otherwise noted.)
A
DD
OUTPUT POWER vs. SUPPLY VOLTAGE
OUTPUT POWER vs. SUPPLY VOLTAGE
OUTPUT POWER vs. SUPPLY VOLTAGE
16
14
12
10
8
16
14
12
10
8
16
14
12
10
8
f
= 315MHz
f
= 433MHz
f
= 315MHz
RF
RF
RF
PA ON
PA ON
PA ON
ENVELOPE SHAPING
DISABLED
T
= -40°C
A
T
= -40°C
T = -40°C
A
A
T
A
= +25°C
T
A
= +25°C
T
= +25°C
A
T = +85°C
A
T
= +85°C
T
= +85°C
A
A
T
= +125°C
T
= +125°C
T = +125°C
A
A
A
6
6
6
4
4
4
2.1
2.4
2.7
3.0
3.3
3.6
2.1
2.4
2.7
3.0
3.3
3.6
2.1
2.4
2.7
3.0
3.3
3.6
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
OUTPUT POWER vs. SUPPLY VOLTAGE
PHASE NOISE vs. OFFSET FREQUENCY
16
14
12
10
8
-40
f
= 433MHz
RF
-50
-60
-70
-80
-90
PA ON
ENVELOPE SHAPING
DISABLED
T
= -40°C
A
f
= 315MHz
= 433MHz
RF
T
= +25°C
A
T
= +85°C
A
f
RF
-100
-110
-120
-130
-140
T
= +125°C
A
6
4
2.1
2.4
2.7
3.0
3.3
3.6
100
1k
10k
100k
1M
10M
SUPPLY VOLTAGE (V)
OFFSET FREQUENCY (Hz)
CLOCK SPUR MAGNITUDE
vs. SUPPLY VOLTAGE
FREQUENCY STABILITY
vs. SUPPLY VOLTAGE
-40
-45
-50
-55
-60
-65
-70
10
8
f
= 315MHz
RF
CLKOUT SPUR = f
f
RF CLKOUT
10pF LOAD CAPACITANCE
6
f
= 315MHz
RF
4
f
= f /16
CLKOUT XTAL
2
0
-2
-4
-6
-8
-10
f
= 433MHz
RF
f
= f
/8
CLKOUT XTAL
f
= f
/4
CLKOUT XTAL
2.1
2.4
2.7
3.0
3.3
3.6
2.1
2.4
2.7
3.0
3.3
3.6
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
_______________________________________________________________________________________
5
300MHz to 450MHz Low-Power,
Crystal-Based +10dBm ASK/FSK Transmitter
Pin Description
PIN
NAME
DESCRIPTION
1
V
Supply Voltage. Bypass to GND with a 10nF and 220pF capacitor as close to the pin as possible.
DD
Mode Select. A logic low on MODE enables the device in ASK mode. A logic high on MODE enables the
device in FSK mode.
2
3
MODE
DIN
Data Input. Power amplifier is on when DIN is high in ASK mode. Frequency is high when DIN is high in
FSK mode.
MAX1479
4
5
ENABLE Standby/Power-Up Input. A logic low on ENABLE sets the device in standby mode.
CLKOUT Buffered Clock Output. Programmable through CLK0 and CLK1. See Table 1.
Power-Amplifier Supply Voltage. Bypass to GND with a 10nF and 220pF capacitor as close to the pin as
6
7
8
V
PA
DD_
possible.
Envelope-Shaping Output. ROUT controls the power-amplifier envelope rise and fall. Bypass to GND with a
680pF and 220pF capacitor as close to the pin as possible.
ROUT
Power-Amplifier Output. Requires a pullup inductor to the supply voltage, which can be part of the output-
matching network to an antenna.
PAOUT
9
CLK0
CLK1
DEV0
DEV1
DEV2
XTAL1
XTAL2
GND
1st Clock Divider Setting. See Table 1.
10
11
12
13
14
15
16
2nd Clock Divider Setting. See Table 1.
1st FSK Frequency-Deviation Setting. See Table 2.
2nd FSK Frequency-Deviation Setting. See Table 2.
3rd FSK Frequency-Deviation Setting. See Table 2.
1st Crystal Input. f = 32 x f
.
RF
XTAL
2nd Crystal Input. f = 32 x f
.
RF
XTAL
Ground. Connect to system ground.
Exposed Ground Pad. EP is the power amplifier’s ground. It must be connected to PCB through a low-
inductance path.
—
EP
oscillator is running, the 300kHz PLL bandwidth allows
fast frequency recovery during power-amplifier toggling.
Detailed Description
The MAX1479 is a highly integrated ASK/FSK transmit-
ter operating over the 300MHz to 450MHz frequency
band. The device requires only a few external compo-
nents to complete a transmitter solution. The MAX1479
includes a complete PLL and a highly efficient power
amplifier. The device can be set into a 0.2nA low-power
shutdown mode.
Mode Selection
MODE (pin 2) sets the MAX1479 in either ASK or FSK
mode. When MODE is set low, the device operates as
an ASK transmitter. If MODE is set high, the device
operates as an FSK transmitter. In the ASK mode, the
DIN pin controls the output of the power amplifier. A
logic low on DIN turns off the PA, and a logic high turns
on the PA. In the FSK mode, a logic low on the DIN pin
is represented by the low FSK frequency, and a logic-
high input is represented by the high FSK frequency.
(The ASK carrier frequency and the lower FSK frequen-
cy are the same.) The deviation is proportional to the
crystal load impedance and pulling capacitance. The
Shutdown Mode
ENABLE (pin 4) is internally pulled down with a 20µA
current source. If it is left unconnected or pulled low,
the MAX1479 goes into a low-power shutdown mode.
In this mode, the supply current drops to 0.2nA. When
ENABLE is high, the device is enabled and is ready for
transmission after 200µs (frequency settles to within
50kHz).
maximum frequency deviation is 55kHz for f
=
RF
315MHz and 80kHz for f = 433MHz.
RF
The 200µs turn-on time of the MAX1479 is mostly domi-
nated by the crystal oscillator startup time. Once the
6
_______________________________________________________________________________________
300MHz to 450MHz Low-Power,
Crystal-Based +10dBm ASK/FSK Transmitter
MAX1479
Clock Output
The MAX1479 has a dedicated digital output pin for the
frequency-divided crystal clock signal. This is to be
used as the time base for a microprocessor. The fre-
quency-division ratio is programmable through two dig-
ital input pins (CLK0, CLK1), and is defined in Table 1.
The clock output is designed to drive a 3.5MHz CMOS
rail-to-rail signal into a 10pF capacitive load.
Table 1. Clock Divider Settings
CLK1
CLK0
CLKOUT
0
0
1
1
0
1
0
1
Logic 0
F
XTAL
F
XTAL
/4
/8
f
/16
XTAL
Envelope-Shaping Resistor
The envelope-shaping resistor allows for a gentle turn-
on/turn-off of the PA in ASK mode. This results in a small-
er spectral width of the modulated PA output signal.
Table 2. Frequency-Deviation Settings
DEV2
DEV1
DEV0
DEVIATION
1/8 x max
1/4 x max
3/8 x max
1/2 x max
5/8 x max
3/4 x max
7/8 x max
Max
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
Phase-Locked Loop
The PLL block contains a phase detector, charge
pump, integrated loop filter, VCO, asynchronous 32x
clock divider, and crystal oscillator. The PLL requires
no external components. The relationship between the
carrier and crystal frequency is given by:
f
= f /32
RF
XTAL
Crystal Oscillator
The crystal oscillator in the MAX1479 is designed to
present a capacitance of approximately 3pF to ground
from the XTAL1 and XTAL2 pins in ASK mode. In most
cases, this corresponds to a 4.5pF load capacitance
applied to the external crystal when typical PCB para-
sitics are added. In FSK mode, a percentage (defined
by bits DEV0 to DEV2) of the 3pF internal crystal oscil-
lator capacitance is removed for a logic 1 on the DIN
pin to pull the transmit frequency. The frequency devia-
tion is shown in Table 2. It is very important to use a
crystal with a load capacitance that is equal to the
capacitance of the MAX1479 crystal oscillator plus
PCB parasitics. If very large FSK frequency deviations
are desired, use a crystal with a larger motional capaci-
tance and/or reduce PCB parasitic capacitances.
Application Circuit delivers +10dBm at a supply volt-
age of +2.7V, and draws a supply current of 6.7mA for
ASK/OOK operation (V
at 50% duty cycle) and
DIN
10.5mA for FSK operation. Thus, the overall efficiency
at 100% duty cycle is 35%. The efficiency of the power
amplifier itself is about 50%. An external resistor at
ROUT sets the output power.
Applications Information
Output Matching to 50Ω
When matched to a 50Ω system, the MAX1479 PA is
capable of delivering more than +10dBm of output
power at V
= 2.7V. The output of the PA is an open-
DD
drain transistor that requires external impedance
matching and pullup inductance for proper biasing.
Power Amplifier
The PA of the MAX1479 is a high-efficiency, open-drain,
switch-mode amplifier. With a proper output-matching
network, the PA can drive a wide range of impedances,
including small-loop PCB trace antennas and any 50Ω
antennas. The output-matching network for a 50Ω anten-
na is shown in the Typical Application Circuit. The out-
put-matching network suppresses the carrier harmonics
and transforms the antenna impedance to an optimal
impedance at PAOUT (pin 8), which is about 250Ω.
The pullup inductance from PAOUT to V
serves three
DD
main purposes: It forms a resonant tank circuit with the
capacitance of the PA output, provides biasing for the
PA, and becomes a high-frequency choke to reduce
the RF energy coupling into V . Maximum efficiency is
DD
achieved when the PA drives a load of 250Ω. The rec-
ommended output-matching network topology is shown
in the Typical Application Circuit.
When the output-matching network is properly tuned,
the power amplifier is highly efficient. The Typical
_______________________________________________________________________________________
7
300MHz to 450MHz Low-Power,
Crystal-Based +10dBm ASK/FSK Transmitter
The objective of the matching network is to match the
power-amplifier output to the impedance of the small-
loop antenna. The matching components thus tune out
the loop inductance and transform the low radiative
and resistive parts of the antenna into the much higher
value of the PA output. This gives higher efficiency. The
low radiative and lossy components of the small-loop
antenna result in a higher Q matching network than the
50Ω network; thus, the harmonics are lower.
Output Matching to
PCB Loop Antenna
In most applications, the MAX1479 power-amplifier out-
put has to be impedance matched to a small-loop
antenna. The antenna is usually fabricated out of a cop-
per trace on a PCB in a rectangular, circular, or square
pattern. The antenna has an impedance that consists of
a lossy component and a radiative component. To
achieve high radiating efficiency, the radiative compo-
nent should be as high as possible, while minimizing
the lossy component. In addition, the loop antenna has
an inherent loop inductance associated with it (assum-
ing the antenna is terminated to ground). For example,
in a typical application, the radiative impedance is less
than 0.5Ω, the lossy impedance is less than 0.7Ω, and
the inductance is approximately 50nH to 100nH.
MAX1479
Layout Considerations
A properly designed PCB is an essential part of any
RF/microwave circuit. On the power-amplifier output,
use controlled-impedance lines and keep them as short
as possible to minimize losses and radiation.
Keeping the traces short reduces parasitic inductance.
Generally, 1in of PCB trace adds about 20nH of para-
sitic inductance. Parasitic inductance can have a dra-
matic effect on the effective inductance. For example, a
0.5in trace connecting a 100nH inductor adds an extra
10nH of inductance, or 10%.
Table 3. Component Values for Typical
Application Circuit
VALUE FOR
VALUE FOR
COMPONENT
f
= 433MHz
f
= 315MHz
RF
RF
To reduce the parasitic inductance, use wider traces
and a solid ground or power plane below the signal
traces. Using a solid ground plane can reduce the par-
asitic inductance from approximately 20nH/in to 7nH/in.
Also, use low-inductance connections to ground on all
GND pins and place decoupling capacitors close to all
L1
L3
22nH
18nH
6.8pF
10pF
27nH
22nH
15pF
C1
C2
22pF
C3
10nF
10nF
V
DD
connections.
C4
680pF
6.8pF
220pF
10nF
680pF
15pF
C6
C8
220pF
10nF
C10
C11
C12
C14
C15
220pF
220pF
100pF
100pF
220pF
220pF
100pF
100pF
8
_______________________________________________________________________________________
300MHz to 450MHz Low-Power,
Crystal-Based +10dBm ASK/FSK Transmitter
MAX1479
Typical Application Circuit
C15
C14
16
15
14
13
V
CC
FREQUENCY-
DEVIATION
INPUTS
V
DEV1
DEV0
CLK1
CLK0
DD
CRYSTAL
DRIVER
1
2
3
4
DEVIATION
12
11
10
9
C10
C11
LOOP
FILTER
PD/CP
MODE
MODE-SELECT
INPUT
ASK
FSK
DIVIDE
BY 32
VCO
PA
DIN
DATA INPUT
CLOCK-
DIVIDER
INPUTS
MAX1479
CLOCK
DIVIDER
ENVELOPE
SHAPING
ENABLE
ENABLE INPUT
5
6
7
8
L1
V
CC
C12
C8
C4
C1
L3
CLOCK
OUTPUT
RF
OUTPUT
C3
C2
C6
Chip Information
Package Information
For the latest package outline information and land patterns, go
PROCESS: CMOS
to www.maxim-ic.com/packages.
PACKAGE TYPE PACKAGE CODE DOCUMENT NO.
16 TQFN-EP
T1633+2
21-0136
_______________________________________________________________________________________
9
300MHz to 450MHz Low-Power,
Crystal-Based +10dBm ASK/FSK Transmitter
Revision History
REVISION REVISION
PAGES
CHANGED
DESCRIPTION
NUMBER
DATE
0
1
8/04
Initial release
Changed part number in Ordering Information to lead free and corrected errors
—
6/09
1, 2, 7
MAX1479
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
10 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2009 Maxim Integrated Products
Maxim is a registered trademark of Maxim Integrated Products, Inc.
相关型号：
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MAXIM
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