MAX2754EUA [MAXIM]
1.2GHz VCO with Linear Modulation Input; 1.2GHz的VCO，带有线性调制输入
| 型号： | MAX2754EUA |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | 1.2GHz VCO with Linear Modulation Input |
| 文件： | 总8页 (文件大小：175K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-2102; Rev 1; 8/03
1.2GHz VCO with Linear
Modulation Input
General Description
Features
The MAX2754 self-contained, linear modulation, volt-
age-controlled oscillator (VCO) is intended for use in
the 2.4GHz to 2.5GHz ISM band, particularly for FSK
modulation systems that utilize a direct frequency-mod-
ulation transmit architecture. This device features a lin-
ear modulation input in addition to the standard
frequency tuning input. The frequency tuning range of
1145MHz to 1250MHz (1/2 LO) also supports an IF up
to 110MHz with low side LO. The VCO is based on
Maxim’s proprietary monolithic VCO technology, where
all VCO components are integrated on-chip, including
the varactor and inductor.
o Fully Monolithic VCO Construction with On-Chip
Inductor and Varactor Tuning Elements
o Guaranteed 1145MHz to 1250MHz Tuning Range
to Support 1/2 LO Applications
o Modulation Linearity Within 4ꢀ
o Precise Modulation Gain (-500kHz/V)
o Low Phase Noise (-137dBc/Hz at 4MHz offset)
o +2.7V to +5.5V Single-Supply Operation
o Low-Current Shutdown Mode
The MAX2754 linear modulation input offers a means to
directly FM modulate the VCO with a constant modula-
tion sensitivity over the tuning voltage input range.
Typical frequency deviation is -500kHz/V which is linear
to 4ꢀ over the guaranteed frequency limits. The tun-
ing input voltage range is +0.4V to +2.4V and the oscil-
lator frequency is factory adjusted to provide
guaranteed limits. The oscillator signal is buffered by
an output amplifier stage (internally matched to 50Ω) to
provide higher output power and isolate the oscillator
from load impedance variations.
o Miniature 8-Pin µMAX Package
Ordering Information
PART
TEMP RANGE
PIN-PACKAGE
MAX2754EUA
-40°C to +85°C
8 µMAX
The MAX2754 operates over a +2.7V to +5.5V supply
range. This device also provides a digitally controlled
shutdown mode to permit implementation of sophisti-
cated power-supply management. In shutdown, the
supply current is reduced to 0.2µA. Even when active,
power consumption is a modest 41mW.
8-pin µMAX
✕
(3mm 5mm)
The MAX2754 is packaged in the miniature 8-pin µMAX
to offer the world’s smallest, complete 2.4GHz direct-
modulation VCO solution.
Typical Operating Circuit
Applications
HomeRF WLAN
V
CC
Bluetooth
V
VREG
CC
REG AND BIAS
2.4GHz Cordless Phones
2.4GHz Wireless Data Radios
330nF
330nF
OUT TO
TUNE
TUNE
OSCILLATOR
CORE
OUT
Pin Configuration
MIXER/
SYNTHESIZER
TOP VIEW
GND1
GND2
SHDN
VREG
TUNE
GND1
MOD
1
2
3
4
8
7
6
5
V
CC
OUT
LINEAR
MODULATION
INTERFACE
MAX2754
MODULATION
MOD
SHDN
GND2
SHDN
VOLTAGE
SIGNAL
MAX2754
µMAX
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
1.2GHz VCO with Linear
Modulation Input
ABSOLUTE MAXIMUM RATINGS
CC
VREG to GND........................................................-0.3V to +6.0V
TUNE, SHDN, MOD to GND.......................-0.3V to (V + 0.3V)
V
to GND...........................................................-0.3V to +6.0V
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range.............................-65°C to +160°C
Lead Temperature (soldering, 10s) .................................+300°C
CC
OUT to GND ..........................................................-0.3V to +6.0V
Continuous Power Dissipation (T = +70°C)
A
8-Pin µMAX (derate 5.7mW/°C above T = +70°C) ....457mW
A
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.
CAUTION! ESD SENSITIVE DEVICE
DC ELECTRICAL CHARACTERISTICS
(V
= +2.7V to +5.5V, V
= +0.4V to +2.4V, V
≥ +2.0V, V
= +1.4V, OUT is connected to a 50Ω load, T = -40°C to
MOD A
CC
TUNE
SHDN
+85°C. Typical values are at V
= +3.0V, T = +25°C, unless otherwise noted.) (Note 1)
CC
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
13.7
0.2
MAX
5.5
16.4
20
UNITS
Supply Voltage
V
2.7
V
CC
T
T
= +25°C, V
≥ 2.0V
SHDN
A
A
mA
Supply Current
I
= -40°C to +85°C, V
≥ 2.0V
CC
SHDN
V
≤ 0.6V
-2
2
µA
V
SHDN
Digital Input Voltage High
Digital Input Voltage Low
Digital Input Current High
Digital Input Current Low
V
2.0
IH
V
0.6
2
V
IL
I
V
V
≥ 2.0V
≤ 0.6V
-2
-1
µA
µA
V
IH
SHDN
SHDN
I
1
IL
Modulation Input Voltage Range
TUNE Leakage Current (Note 2)
V
0.4
2.4
MOD
V
= +0.4V to +2.4V
0.01
nA
TUNE
AC ELECTRICAL CHARACTERISTICS
(MAX2754 EV kit. V
= +2.7V to +5.5V, V
= +0.4V to +2.4V, V
≥ +2.0V, V
= +1.4V, OUT is connected to a 50Ω load,
MOD
CC
TUNE
SHDN
T
= +25°C. Typical values are at V
= +3.0V, T = +25°C, unless otherwise noted.) (Note 1)
A
CC A
PARAMETER
SYMBOL
CONDITIONS
= +0.4V to +2.4V,
MIN
TYP
MAX
UNITS
Oscillator Guaranteed Frequency
Limits
f
f
,
V
TUNE
MIN
MAX
1145
1250
MHz
T
= -40°C to +85°C
A
f
= 4MHz
-137
-151
124
81
dBc/Hz
dBm/Hz
OFFSET
Phase Noise
Noise floor
V
V
at f
at f
TUNE
TUNE
MIN
Tuning Gain
MHz/V
dBm
MAX
Output Power
-5
Modulation Peak Frequency
Deviation
f
< f < f
(Note 2)
400
500
600
kHz
MIN
MAX
Modulation Sensitivity
Common-mode V
= 1.4V
-500
kHz/V
MOD
2
_______________________________________________________________________________________
1.2GHz VCO with Linear
Modulation Input
AC ELECTRICAL CHARACTERISTICS (continued)
(MAX2754 EV kit. V
= +2.7V to +5.5V, V
= +0.4V to +2.4V, V
≥ +2.0V, V
= +1.4V, OUT is connected to a 50Ω load,
MOD
CC
TUNE
SHDN
T
= +25°C. Typical values are at V
= +3.0V, T = +25°C, unless otherwise noted.) (Note 1)
A
CC A
PARAMETER
SYMBOL
CONDITIONS
= +0.4 to +2.4V,
MIN
TYP
MAX
UNITS
V
MOD
Modulation Linearity
4
%
f
< f < f
(Note 4)
MIN
MAX
Modulation Full-Power Bandwidth
(Note 5)
2.5
MHz
Return Loss (Note 6)
Output Harmonics
f
< f < f
7.5
-20
1.5
0.16
10
dB
MIN
MAX
dBc
Load Pulling
VSWR = 2:1, all phases
stepped: +3.3V to +2.8V
MHz
p-p
Supply Pushing
V
MHz/V
µs
CC
Oscillator Turn-On Time (Note 7)
Oscillator Turn-Off Time (Note 8)
8
µs
Note 1: Specifications are production tested at T = +25°C. Limits over temperature are guaranteed by design and characterization.
A
Note 2: Limits are guaranteed by production test at +25°C.
Note 3: Center point is nominally +1.4V.
Note 4: Maximum variation in the modulation sensitivity from its average value over the guaranteed frequency limits.
Note 5: Bandwidth is defined as the point where the response to the modulation port is 0.707 times the low-frequency response.
Bandwidth limits on the modulation input for a 1Vp-p sine wave. Common-mode V
Note 6: Refer to Output Buffer section for suggestions to improve the return loss to 12dB.
Note 7: Turn-on time to within 3dB of final output power.
= +1.4V.
MOD
Note 8: Turn-off time to output power of -10dBm.
_______________________________________________________________________________________
3
1.2GHz VCO with Linear
Modulation Input
Typical Operating Characteristics
(MAX2754 EV kit, V
= +3.0V, V
≥ +2.0V, V
= V
= +1.4V, and T = +25°C, unless otherwise noted.)
CC
SHDN
TUNE
MOD A
VCO TUNING CURVE
MODULATION SENSITIVITY vs.
CARRIER FREQUENCY
TUNE INPUT CURRENT
vs. TEMPERATURE
1350
1300
1250
1200
1150
1100
1050
1000
950
-400
-420
-440
-460
-480
-500
-520
-540
-560
-580
-600
1.0
0.8
0.6
0.4
0.2
0
T
= -40°C
A
T
= -40°C
A
T
= +25°C
A
T
= +85°C
A
T
= +25°C
A
T
= +85°C
A
0
0.5
1.0
1.5
2.0
2.5
3.0
1140 1160 1180 1200 1220 1240 1260
CARRIER FREQUENCY (MHz)
-40
-15
10
35
60
85
V
(V)
TUNE
TEMPERATURE (°C)
OUTPUT POWER vs. FREQUENCY
OUTPUT POWER
vs. FREQUENCY
NORMALIZED HARMONIC
OUTPUT SPECTRUM
-3.0
-3.5
-4.0
-4.5
-5.0
-5.5
-6.0
-2
-3
-4
-5
-6
-7
-8
T
= +85°C
A
∆ = -20dBc
V
= +5.5V
CC
∆ = -30dBc
V
= +4.0V
CC
T
= +25°C
A
V
= +2.7V
CC
T
= -40°C
A
1140 1160 1180 1200 1220 1240 1260
FREQUENCY (MHz)
ƒ
3ƒ
O
2ƒ
1140 1160 1180 1200 1220 1240 1260
FREQUENCY (MHz)
O
O
FREQUENCY
OSCILLATOR TURN-ON/
TURN-OFF TIME
PHASE NOISE
OUTPUT S
11
0
-60
0
-5
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
-70
-80
SHDN LOW-TO-HIGH
AT TIME = 0
-90
-100
-110
-120
-130
-140
-150
-160
-10
-15
-20
SHDN HIGH-TO-LOW
AT TIME = 0
0
10
20
30
40
50
10
100
1000
10,000
800 900 1000 1100 1200 1300 1400 1500 1600
FREQUENCY (MHz)
TIME (µs)
OFFSET FREQUENCY (kHz)
4
_______________________________________________________________________________________
1.2GHz VCO with Linear
Modulation Input
Pin Description
PIN
1
NAME
VREG
TUNE
FUNCTION
Capacitor Connection to the On-Chip Linear Regulator Output. Connect a 330nF capacitor to ground.
Oscillator Frequency Tuning-Voltage Input. High-impedance input with a voltage range of +0.4V (low
frequency) to +2.4V (high frequency).
2
Ground Connection for the Oscillator Core. Requires a low-inductance connection to the circuit-
board ground plane.
3
4
5
GND1
MOD
Linear Modulation Input. High-impedance CMOS input with a voltage range of +0.4V to +2.4V.
Shutdown Input. Drive logic low to place the device in shutdown mode. Drive logic high for normal
operation.
SHDN
Ground Connection for Output-Buffered Amplifier, Linear Modulation Interface, and Biasing.
Requires a low-inductance connection to the circuit-board ground plane.
6
7
8
GND2
OUT
Buffered Oscillator Output. Incorporates an internal DC-blocking capacitor. OUT is internally
matched to 50Ω.
Supply Voltage Connection. Requires external RF bypass capacitor to ground for low noise and low
spurious content performance from the oscillator. Bypass with a 330pF capacitor to ground.
V
CC
tion frequency. This convention for the modulation gain
Detailed Description
is due to the practical implementation of the internal lin-
Oscillator
earizing circuitry. This gain inversion must be consid-
ered when designing the analog voltage interface that
drives the linear modulation input. The easiest way to
handle this is to invert the logic polarity of the modula-
tion data three-state output buffer (TX data output).
Where it is impossible to invert the data-stream logic
polarity, an external inverter and three-state buffer
would be required. These devices are offered in small
single-logic gates in SC-79 style packages from various
manufacturers (e.g., Fairchild—Tiny Logic, On
Semiconductor, or Rohm).
The MAX2754 VCO is implemented as an LC oscillator
topology, integrating all of the tank components on-
chip. This fully monolithic approach provides an
extremely easy-to-use VCO, equivalent to a VCO mod-
ule. The frequency is controlled by a voltage applied to
the TUNE pin. The VCO core uses a differential topolo-
gy to provide a stable frequency versus supply voltage
and improve the immunity to load variations. In addi-
tion, there is a buffer amplifier following the oscillator
core to provide added isolation from load and supply
variations and to boost the output power.
Figure 1 illustrates the frequency versus V
charac-
MOD
teristic of the modulation input. Note the negative slope
of the curve, df /dV < 0, where f = f
NOM
Linear Modulation
The linear modulation input offers a means to directly
FM modulate the VCO with a controlled amount of fre-
quency deviation for a given input voltage deviation.
The unique technique maintains a consistent modula-
-
OUT
MOD
MOD
MOD
f
.
Output Buffer
The oscillator signal from the core drives an output
buffer amplifier. The amplifier is internally matched to
50Ω including an on-chip DC-blocking capacitor. The
return loss can be improved to a minimum of 12dB over
1145MHz to 1250MHz by adding a 2.5nH series induc-
tor and a 3.0pF shunt capacitor. The output buffer has
a ground connection separate from the oscillator core
to minimize load-pulling effects. The amplifier boosts
the oscillator signal to a level suitable for driving most
RF mixers.
tion gain (df/dV
) across the entire frequency tuning
MOD
range of the part, enabling accurate FM modulation
derived solely from the filtered NRZ “data” stream (the
modulation voltage input).
The modulation input is single-ended and centered
about +1.4V. The linear modulation full-scale range is
1V around this point, for a +0.4V to +2.4V input volt-
age range. A very important point to note is that the
sign of the modulation gain is negative. A positive
change in V
results in a negative change in oscilla-
MOD
_______________________________________________________________________________________
5
1.2GHz VCO with Linear
Modulation Input
Applications Information
Tune Input
The tuning input is typically connected to the output of
the PLL loop filter. The loop filter provides an appropri-
ately low-impedance source. Incorporate an extra RC
filter stage to reduce high-frequency noise and spuri-
ous signals. Any excess noise on the tuning input is
directly translated into FM noise, which can degrade
the phase-noise performance of the oscillator.
Therefore, it is important to minimize the noise intro-
duced on the tuning input. A simple RC filter with low
corner frequency is needed during testing to filter the
noise present on the voltage source driving the tuning
line.
f
+ f
NOM MOD
f
NOM
f
- f
NOM MOD
0.5
1.0
1.5
2.0
(V)
2.5
Two-Level FSK Applications
The MAX2754 is designed for use in FSK applications
operating in the 2.4GHz to 2.5GHz ISM band. Specifically,
it is targeted for those systems which utilize a direct TX
modulation architecture in which the VCO is directly modu-
lated with the data signal during the transmit (TX) mode.
The VCO in these systems runs at half the RF output
frequency and is used in conjunction with a frequency
doubler to produce the final LO signal for both RX and
TX modes of operation.
MODULATION VOLTAGE, V
MOD
Figure 1. Modulation Frequency Deviations Characteristics
Figure 2 shows a typical applications circuit. To com-
pute R1, R2, R3, and R4, determine the modulation
voltage center point (V
required modulation voltage deviation as follows:
= +1.4V). Compute the
MODB
V
CC
V
VREG
CC
REG AND BIAS
330nF
330nF
OUT TO
TUNE
OSCILLATOR
CORE
OUT
V
FROM PLL
LOOP FILTER
CC
MIXER/
SYNTHESIZER
R1
R3
R2
INVERTED
CMOS
SIGNAL
GND1
MOD
GND2
SHDN
MOD.
FILTER
LINEAR
MODULATION
INTERFACE
FROM BASEBAND
DIGITAL
CONTROLLER
R4
MAX2754
Figure 2. Typical Application Circuit for Two-Level FSK
6
_______________________________________________________________________________________
1.2GHz VCO with Linear
Modulation Input
∆V = ∆f / 500kHz/V (nominal modulation sensitivity)
Layout Issues
Use controlled impedance lines (microstrip, co-planar
waveguide, etc.) each time for high-frequency signals.
Always place decoupling capacitors as close to the
Let R = R + R + R . Setting R based on the desired
1
3
CC
4
current from V
and filter impedance level:
V
pins as possible; for long V
lines, it may be nec-
CC
CC
essary to add additional decoupling capacitors located
further from the device. Always provide a low-induc-
tance path to ground, and keep GND vias as close to
the device as possible. Thermal reliefs on GND pads
are not recommended.
R
R1 =
R2 =
,
2
V
R
4
MODB
− 1
×
,
,
∆V
V
1
MODB
R3 = R ×
−
Chip Information
2
V
CC
TRANSISTOR COUNT: 619
V
MODB
R4 =
× R
V
CC
_______________________________________________________________________________________
7
1.2GHz VCO with Linear
Modulation Input
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information
go to www.maxim-ic.com/packages.)
4X S
8
8
MILLIMETERS
INCHES
DIM MIN
MAX
MAX
MIN
-
-
0.043
0.006
0.037
0.014
0.007
0.120
1.10
0.15
0.95
0.36
0.18
3.05
A
0.002
0.030
0.010
0.005
0.116
0.05
0.75
0.25
0.13
2.95
A1
A2
b
E
H
ÿ 0.50 0.1
c
D
e
0.0256 BSC
0.65 BSC
0.6 0.1
E
H
0.116
0.188
0.016
0∞
0.120
2.95
4.78
0.41
0∞
3.05
5.03
0.66
6∞
0.198
0.026
6∞
L
1
1
α
S
0.6 0.1
0.0207 BSC
0.5250 BSC
BOTTOM VIEW
D
TOP VIEW
A1
A2
A
c
α
e
L
b
SIDE VIEW
FRONT VIEW
PROPRIETARY INFORMATION
TITLE:
PACKAGE OUTLINE, 8L uMAX/uSOP
APPROVAL
DOCUMENT CONTROL NO.
REV.
1
21-0036
J
1
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.
8 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2003 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
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