MAX7034 查看數據表（PDF） - Maxim Integrated
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MAX7034 Datasheet PDF : 14 Pages
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MAX7034
315MHz/434MHz ASK Superheterodyne
Receiver
Functional Diagram
LNASRC EN_REG LNAOUT MIXIN1 MIXIN2
4
15
6
8
9
IRSEL
11
MIXOUT
12
IFIN1 IFIN2
17 18
LNAIN 3
AVDD 2
VDD5 24
AVDD 7
DVDD 14
DGND 13
AGND 5, 10
LNA
3.4V REG
DIVIDE
BY 64
VCO
PHASE
DETECTOR
LOOP
FILTER
1
CRYSTAL
2
DRIVER
16
XTALSEL
1 28
XTAL1 XTAL2
0˚
Q
IMAGE
REJECTION
90˚
I
MAX7034
IF LIMITING
AMPS
RSSI
DATA
FILTER
RDF2
RDF1
100kΩ
100kΩ
POWER-
DOWN
DATA
SLICER
27
25
SHDN DATAOUT
20 23 19
DSN DSP DFO
26
21
PDOUT OPP
22
DFFB
Detailed Description
The MAX7034 CMOS superheterodyne receiver and a few
external components provide the complete receive chain
from the antenna to the digital output data. Depending on
signal power and component selection, data rates can be
as high as 33kbps Manchester (66kbps NRZ).
The MAX7034 is designed to receive binary ASK data
modulated in the 300MHz to 450MHz frequency range.
ASK modulation uses a difference in amplitude of the car-
rier to represent logic 0 and logic 1 data.
Voltage Regulator
For operation with a single +4.5V to +5.5V supply voltage,
connect VDD5 and the EN_REG pin to the supply voltage.
An on-chip voltage regulator drives one of the AVDD pins
(pin 2) to approximately +3.4V. For proper operation,
DVDD and both AVDD pins must be connected together.
For operation with a single +3.0V to +3.6V supply voltage,
connect both the AVDD pins, DVDD, and VDD5 to the sup-
ply voltage and connect the EN_REG pin to ground (which
disables the internal voltage regulator). If the MAX7034 is
powered from +3.0V to +3.6V, the performance is limited
to the -40°C to +105°C range.
In either supply voltage mode, bypass VDD5, DVDD, and
the pin 7 AVDD pin to AGND with 0.01μF capacitors, and
the pin 2 AVDD to AGND with a 0.1μF capacitor, all placed
as close as possible to the pins.
Low-Noise Amplifier
The LNA is an nMOS cascode amplifier with off-chip
inductive degeneration. The gain and noise figures are
dependent on both the antenna matching network at the
LNA input and the LC tank network between the LNA out-
put and the mixer inputs.
The off-chip inductive degeneration is achieved by con-
necting an inductor from LNASRC to AGND. This inductor
sets the real part of the input impedance at LNAIN, allow-
ing for a more flexible input impedance match, such as a
typical printed-circuit board (PCB) trace antenna. A nomi-
nal value for this inductor with a 50Ω input impedance is
15nH, but is affected by the PCB trace.
The LC tank filter connected to LNAOUT comprises L1
and C9 (see the Typical Application Circuit). Select L1
and C9 to resonate at the desired RF input frequency. The
resonant frequency is given by:
f RF = 2π
1
L TOTAL × C TOTAL
where:
LTOTAL = L1 + LPARASITICS.
CTOTAL = C9 + CPARASITICS.
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