General Description

The MAX191 is a monolithic, CMOS, 12-bit analog-to-

digital converter (ADC) featuring differential inputs,

track/hold (T/H), internal voltage reference, internal or

external clock, and parallel or serial µP interface. The

MAX191 has a 7.5µs conversion time, a 2µs acquisition

time, and a guaranteed 100ksps sample rate.

The MAX191 operates from a single +5V supply or from

dual ±5V supplies, allowing ground-referenced bipolar

input signals. The device features a logic power-down

50µA max, including the internal-reference current.

Decoupling capacitors are the only external compo-

nents needed for the power supply and reference. This

ADC operates with either an external reference, or an

internal reference that features an adjustment input for

trimming system gain errors.

The MAX191 provides three interface modes: two 8-bit

parallel modes, and a serial interface mode that is com-

interface standards.

________________________Applications

Battery-Powered Data Logging

PC Pen Digitizers

High-Accuracy Process Control

Electromechanical Systems

Data-Acquisition Boards for PCs

Automatic Testing Systems

Telecommunications

Digital Signal Processing (DSP)

____________________________Features

o 12-Bit Resolution, 1/2LSB Linearity

o +5V or ±5V Operation

o Built-In Track/Hold

o Internal Reference with Adjustment Capability

o Low Power: 3mA Operating Mode

20µA Power-Down Mode

o 100ksps Tested Sampling Rate

o Serial and 8-Bit Parallel µP Interface

o 24-Pin Narrow DIP and Wide SO Packages

Low-Power, 12-Bit Sampling ADC

with Internal Reference and Power-Down

________________________________________________________________

Maxim Integrated Products

1

24

23

22

21

20

19

18

17

1

2

3

4

5

6

7

8

CLK/SCLK

PAR

HBEN

AIN-

AIN+

PD

TOP VIEW

CS

RD

D7/DOUT

BIP

AGND

REFADJ

VREF

16

15

14

13

9

10

11

12

D5/SSTRB

D4

D3/D11

D2/D10

DGND

D1/D9

D0/D8

BUSY

DIP/SO

MAX191

Pin Configuration

2.46V

REF

IN REF OUT

12-BIT

SAR ADC

OSC

CONTROL

LOGIC

3-STATE

OUTPUT

8-BIT

BUS

AND

SERIAL

I/O

18

17

16

15

14

13

11

10

20

19

9

21

D7/DOUT

D5/SSTRB

D4

D3/D11

D2/D10

D1/D9

D0/D8

CS

RD

BUSY

HBEN

REFADJ

VREF

AIN +

AIN -

5

6

3

4

24

23

CLK/SCLK

712

PD

1 22

8

AGND

DGND

2

PAR

BIP

MAX191

12

Functional Diagram

19-4506; Rev 4; 2/97

PART

TEMP. RANGE

PIN-PACKAGE

MAX191ACNG

0°C to +70°C

24 Narrow Plastic DIP

24 Wide SO

±1/2

±1

±1/2

ERROR

(LSB)

24 Narrow Plastic DIP

MAX191BCNG

MAX191ACWG

0°C to +70°C

0°C to +70°C

MAX191BCWG

0°C to +70°C 24 Wide SO

±1

MAX191BC/D

Dice*

±1

0°C to +70°C

MAX191AENG

-40°C to +85°C 24 Narrow Plastic DIP ±1/2

MAX191BENG

-40°C to +85°C 24 Narrow Plastic DIP ±1

MAX191AEWG

-40°C to +85°C 24 Wide SO

±1/2

MAX191AMRG

24 Narrow CERDIP** ±1/2

MAX191BMRG

24 Narrow CERDIP** ±1

-55°C to +125°C

-55°C to +125°C

MAX191BEWG

-40°C to +85°C 24 Wide SO

±1

SPI and QSPI are trademarks of Motorola, Inc. MICROWIRE is a trademark of National Semiconductor Corp.

For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.

For small orders, phone 408-737-7600 ext. 3468.

EVALUATION

KIT MANUAL

FOLLOWS

DATA

SHEET

** Contact factory for availability and processing to MIL-STD-883.

Ordering Information