Rainbow Electronics MAX1425 User Manual

General description, Applications, Features

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General Description

The MAX1425 10-bit, monolithic analog-to-digital con-
verter (ADC) is capable of a 20Msps sampling rate. This
device features an internal track-and-hold (T/H) amplifier
for excellent dynamic performance; at the same time, it
minimizes the number of external components. Low
input capacitance of only 8pF minimizes input drive
requirements. A wide input bandwidth (up to 150MHz)
makes this device suitable for digital RF/IF downconvert-
er applications employing undersampling techniques.

The MAX1425 employs a differential pipelined architec-
ture with a wideband T/H amplifier to maximize through-
put while limiting power consumption to only 172mW.
The MAX1425 generates an internal +2.5V reference
that supplies three additional reference voltages
(+3.25V, +2.25V, and +1.25V). These reference volt-
ages provide a differential input range of +2V to -2V.
The analog inputs are biased internally to correct the
DC level, eliminating the need for external biasing on
AC-coupled applications.

A separate +3V digital logic supply input allows for
separation of digital and analog circuitry. The output
data is in two’s complement format. The MAX1425 is
available in the space-saving 28-pin SSOP package.
For a pin-compatible version at a lower data rate, refer
to the MAX1426 data sheet. For a higher data rate, refer
to the MAX1424 data sheet.

Applications

Medical Ultrasound Imaging
CCD Pixel Processing
IR Focal Plane Array
Radar
IF and Baseband Digitization
Set-Top Boxes

Features

♦ Differential Inputs for High Common-Mode

Noise Rejection

♦ Signal-to-Noise Ratio

61dB (at f

= 2MHz)

59.3dB (at f

= 10MHz)

♦ Internal +2.5V Reference
♦ 150MHz Input Bandwidth
♦ Wide ±2V Input Range
♦ Low Power Consumption: 172mW
♦ Separate Digital Supply Input for 3V Logic

Compatibility

♦ Single +5V Supply Operation Possible

MAX1425

10-Bit, 20Msps ADC

________________________________________________________________ Maxim Integrated Products

DGND

OE/PD

CLK

CMLN

CMLP

INN

INP

AGND

CML

REFN

REFIN

REFP

AGND

SSOP

TOP VIEW

MAX1425

CLK

INP

INTERFACE

PIPELINE ADC

REF SYSTEM +

BIAS

OUTPUT

DRIVERS

REF

REFIN REFP

CML REFN

OE/PD

AGND

DGND

D9–D0

INN

T/H

MAX1425

Functional Diagram

19-1597; Rev 0; 1/00

Pin Configuration

Ordering Information

PART

MAX1425CAI

MAX1425EAI

-40°C to +85°C

0°C to +70°C

TEMP. RANGE

PIN-PACKAGE

28 SSOP