MAX7034(2008) 查看數據表（PDF） - Maxim Integrated

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MAX7034
(Rev.:2008)

315MHz/434MHz ASK Superheterodyne Receiver

Maxim Integrated 

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 LNA

2, 7

AVDD

VDD5 24

3.4V REG

DVDD 14

DIVIDE

BY 64

VCO

13

PHASE

DGND

DETECTOR

LOOP

FILTER

AGND 5, 10

÷1

÷2

16

XTALSEL

CRYSTAL

DRIVER

1 28

XTAL1 XTAL2

0˚

Q

IMAGE

REJECTION

∑

90˚

I

MAX7034

IF LIMITING

AMPS

RSSI

DATA

FILTER

RDF2

100kΩ

RDF1

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

carrier to represent logic 0 and logic 1 data.

Voltage Regulator

The MAX7034 is designed to work with a nominal +5.0V

supply voltage. The MAX7034 integrates an internal volt-

age regulator that provides +3.4V to some of the internal

circuits in the device; this voltage is connected to the

AVDD and DVDD pins. The device can be operated from

+3.0V to +3.6V by pulling the EN_REG pin low (which dis-

ables the internal voltage regulator) and connecting the

supply voltage to the AVDD and DVDD pins. If the

MAX7034 is powered from +3.0 to +3.6V, the perfor-

mance is limited to the -40°C to +105°C range.

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 output and the mixer inputs.

The off-chip inductive degeneration is achieved by

connecting an inductor from LNASRC to AGND. This

inductor sets the real part of the input impedance at

LNAIN, allowing for a more flexible input impedance

match, such as a typical printed-circuit board (PCB)

trace antenna. A nominal 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:

fRF

=

2π

1

LTOTAL ×

CTOTAL

where:

LTOTAL = L1 + LPARASITICS.

CTOTAL = C9 + CPARASITICS.

LPARASITICS and CPARASITICS include inductance and

capacitance of the PCB traces, package pins, mixer

input impedance, etc. These parasitics at high frequen-

cies cannot be ignored, and can have a dramatic effect

8 _______________________________________________________________________________________

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