Copyright © 2008, ZMD AG, Rev. 1.1

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ZADCS146/ZADCS147

12-Bit, 200ksps, 8-Channel, Serial Output ADC

Datasheet

Features

·

Single Supply Operation:

+ 2.7V … + 5.25V

·

8-Channel Single-Ended or

4-Channel Differential Inputs

·

Up to 200ksps Conversion Rate

·

± 1 LSB INL and DNL

·

No Missing Codes

·

True fully differential Operation

·

Software-Configurable Unipolar or

Bipolar output coding

·

Internal 3.2MHz oscillator for independent

operation from external clock

·

Internal 2.5V Reference

·

Low Power

-

< 1.2mA (200ksps, 5V supply)

-

< 0.5μA (power-down mode)

·

SPI

4-Wire Serial Interface

·

20-Pin SSOP

·

Alternate Source for MAX146 / MAX147

Applications

·

Data Acquisition

·

Industrial Process Control

·

Portable Data Logging

·

Battery-Powered Systems

Functional Block Diagram

Description

ZADCS146 and ZADCS147 are low power, 12-bit, succes-

sive approximation analog-to-digital (A/D) converters with

up to 200ksps conversion rate, 8-channel input multi-

plexer, high-bandwidth track/hold and synchronous serial

interface.

The ADC operates from a single + 2.7V to + 5.25V supply.

Its analog inputs are software configurable for unipo-

lar/bipolar and single-ended/differential operation.

The 4-wire serial interface connects directly to SPI™/

(QSPI™ and MICROWIRE™) devices without external

logic.

Both devices can use either the external serial-interface

clock or an internal clock to perform successive-

approximation analog-to-digital conversions. The internal

clock can be used to run independent conversions on

more than one device in parallel.

The ZADC146 is equipped with a highly accurate internal

2.5V reference with an additional external ±1.5% voltage

adjustment range.

ZADCS146 / ZADCS147 provide a hard-wired shut-down

pin (nSHDN) pin and software-selectable power-down

modes that can be programmed to automatically shut

down the IC at the end of a conversion. Accessing the

serial interface automatically powers up the IC. A quick

turn-on time allows the device to be shut down between all

conversions.

8-Channel

Analog

Input

Multiplexer

DAC with

inherent

T&H

SAR

Serial

Interface

and

Control

State

Machine

+ 1.25V

Reference

Internal

3.2 MHz

Oscillator

CH0

CH1

CH2

CH3

CH4

CH5

CH6

CH7

COM

REFADJ

VREF

AGND

DGND

VDD

nSHDN

SSTRB

DOUT

DIN

SCLK

nCS

+

-

Comparator

x 2.000

Available in ZADCS146 only

IN+

IN-

Starterkit

available