ADC12762

12-Bit, 1.4 MHz, 300 mW A/D Converter

with Input Multiplexer and Sample/Hold

General Description

Using an innovative multistep conversion technique, the

12-bit ADC12762 CMOS analog-to-digital converter digitizes

signals at a 1.4 MHz sampling rate while consuming a maxi-

mum of only 300 mW on a single +5V supply. The

ADC12762

performs

a

12-bit

conversion

in

three

lower-resolution “flash” conversions, yielding a fast A/D with-

out the cost and power dissipation associated with true flash

approaches.

The analog input voltage to the ADC12762 is tracked and

held by an internal sampling circuit, allowing high frequency

input signals to be accurately digitized without the need for

an external sample-and-hold circuit. The ADC12762 features

two sample-and-hold/flash comparator sections which allow

the converter to acquire one sample while converting the

previous. This pipelining technique increases conversion

speed without sacrificing performance. The multiplexer out-

put is available to the user in order to perform additional ex-

ternal signal processing before the signal is digitized.

When the converter is not digitizing signals, it can be placed

in the Standby mode; typical power consumption in this

mode is 250 µW.

Features

n Built-in sample-and-hold

n Single +5V supply

n Single channel or 2 channel multiplexer operation

Key Specifications

n Sampling rate

1.4 MHz (min)

n Conversion time

593 ns (typ)

67.5 dB (min)

300 mW (max)

n No missing codes over temperature

Guaranteed

Applications

n CCD image scanners

n Digital signal processor front ends

n Instrumentation

n Disk drives

n Mobile telecommunications

n Waveform digitizers

ADC12762 Block Diagram

Ordering Information

Commercial (0˚C

≤ T

Package

ADC12762CCV

V44 Plastic Leaded Chip Carrier

ADC12062EVAL

Evaluation Board

DS012811-1

June 1999

© 1999 National Semiconductor Corporation

DS012811

www.national.com