3-247

TELCOM SEMICONDUCTOR, INC.

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TC7136

TC7136A

A or blank*

R (reversed pins) or blank (CPL pkg only)

* "A" parts have an improved reference TC

Package Code (see below):

TYPICAL APPLICATIONS

s

Thermometry

s

Bridge Readouts: Strain Gauges, Load Cells, Null

Detectors

s

Digital Meters: Voltage/Current/Ohms/Power, pH

s

Digital Scales, Process Monitors

s

Portable Instrumentation

ORDERING INFORMATION

PART CODE

TC7136X X XXX

Package

Temperature

Code

Package

Pin Layout

Range

CKW

44-Pin PQFP

Formed Leads

0

°C to +70°C

CLW

44-Pin PLCC

—

0

°C to +70°C

CPL

40-Pin PDIP

Normal

0

°C to +70°C

40-Pin Plastic DIP

44-Pin Plastic Quad Flat

Package Formed Leads

44-Pin Plastic Chip

Carrier PLCC

+

TC7136

TC7136A

33

34

240 k

Ω

10 k

Ω

31

29

39

38

40

–

0.47

µF

0.1 µF

V

–

1

OSC

3

OSC

2

OSC

TO ANALOG COMMON

(PIN 32)

1 CONVERSION/SEC

COSC

560 k

Ω

180 k

Ω

0.15 µF

0.01 µF

ANALOG

INPUT

+

–

–

+

+

–

ANALOG

COMMON

20

21

1

SEGMENT

DRIVE

9–19

22–25

POL

BP

V

+

MINUS SIGN

BACKPLANE

28

50 pF

LCD

1 M

Ω

27

30

32

35

36

9V

+

ROSC

26

TYPICAL OPERATING CIRCUIT

AVAILABLE PACKAGES

LOW POWER, 3-1/2 DIGIT ANALOG-TO-DIGITAL CONVERTERS

FEATURES

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Fast Overrange Recovery, Guaranteed First

Reading Accuracy

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Low Temperature Drift Internal Reference

TC7136 ....................................... 70 ppm/

TC7136A ..................................... 35 ppm/

s

Guaranteed Zero Reading With Zero Input

s

Low Noise .................................................... 15

P-P

s

High Resolution .............................................. 0.05%

s

Low Input Leakage Current ...................... 1 pA Typ

10 pA Max

s

Precision Null Detectors With True Polarity at

Zero

s

High-Impedance Differential Input

s

Convenient 9V Battery Operation With

Low Power Dissipation ........................ 500

900

GENERAL DESCRIPTION

The TC7136 and TC7136A are low-power, 3-1/2 digit

with liquid crystal display (LCD) drivers with analog-to-

digital converters. These devices incorporate an "integra-

tor output zero" phase which guarantees overrange

recovery. The performance of existing TC7126, TC7126A

and ICL7126-based systems may be upgraded with minor

changes to external, passive components.

The TC7136A has an improved internal zener refer-

ence voltage circuit which maintains the analog common

temperature drift to 35 ppm/

°C (typical) and 75 ppm/°C

(maximum). This represents an improvement of two to four

times over similar 3-1/2 digit converters. The costly, space-

consuming external reference source may be removed.

The TC7136/A limits linearity error to less than 1 count

on 200 mV or 2V full-scale ranges. Roll-over error — the

difference in readings for equal magnitude but opposite

polarity input signals — is below

±1 count. High-impedance

Ω

input impedance. The differential reference input allows

ratiometric measurements for ohms or bridge transducer

measurements. The 15

tees a "rock solid" reading. The auto-zero cycle guarantees

a zero display readout for a 0V input.

TC7136-6

10/18/96