MAX2451 Datasheet, PDF (1/6 Pages) Maxim Integrated Products – 3V, Ultra-Low-Power Quadrature Demodulator

19-0493; Rev 0; 12/95
EVAALVUAAILTAIOBNLEKIT
3V, Ultra-Low-Power
Quadrature Demodulator
_______________General Description
The monolithic MAX2451 is a quadrature demodulator
with a supporting oscillator and divide-by-8 prescaler. It
operates from a single +3V supply and draws only
5.5mA. The demodulator accepts an amplified and fil-
tered IF signal in the 35MHz to 80MHz range, and
demodulates it into I and Q baseband signals with
51dB of voltage conversion gain. The IF input is termi-
nated with a 400Ω thin-film resistor for matching to an
external IF filter. The baseband outputs are fully differ-
ential and have 1.2Vp-p signal swings.
Pulling the CMOS-compatible ENABLE pin low shuts
down the MAX2451 and reduces the supply current to
less than 2µA, typical. To minimize spurious feedback,
the MAX2451’s internal oscillator is set at twice the IF
frequency via external tuning components. The
MAX2451 comes in a 16-pin narrow SO package.
____________________________Features
o Integrated Quadrature Phase Shifters
o On-Chip Oscillator (Requires External Tuning
Circuit)
o 51dB Voltage Conversion Gain
o On-Chip Divide-by-8 Prescaler
o Baseband Output Bandwidth Up to 9MHz
o CMOS-Compatible Enable
o 5.5mA Operating Supply Current
2µA Shutdown Supply Current
________________________Applications
Digital Cordless Phones
GSM and North American Cellular Phones
Wireless LANs
Digital Communications
Pagers
______________Ordering Information
PART
MAX2451CSE
TEMP. RANGE
0°C to +70°C
PIN-PACKAGE
16 Narrow SO
________________Functional Diagram
__________________Pin Configuration
TOP VIEW
IF 1
GND 2
GND 3
N.C. 4
ENABLE 5
PRE_OUT 6
LO_V_CC 7
TANK 8
MAX2451
SO
16 GND
15 V_CC
14 I
13 I
12 Q
11 Q
10 LO_GND
9 TANK
DEMODULATOR
IF ¹
400Ω
14
I
13
I
BIAS
12
Q
11
Q
LO_VCC ⁷
TANK ⁸
TANK ⁹
LO_GND ¹⁰
VCC ¹⁵
÷ 2 ^0°
QUADRATURE
PHASE
GENERATOR
LOCAL
OSCILLATOR
÷ 2 ^90°
÷4
PRESCALER
6
PRE_OUT
MAX2451
MASTER BIAS
BANDGAP
BIAS
2, 3, 16
GND
5
ENABLE
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