3-113

TELCOM SEMICONDUCTOR, INC.

7

6

5

4

3

1

2

8

GENERAL DESCRIPTION

The TC7135 4-1/2 digit analog-to-digital converter (ADC)

offers 50 ppm (1 part in 20,000) resolution with a maximum

nonlinearity error of 1 count. An auto-zero cycle reduces zero

error to below 10

µV and zero drift to 0.5 µV/°C. Source

impedance errors are minimized by a 10 pA maximum input

current. Roll-over error is limited to

±1 count.

By combining the TC7135 with a TC7211A (LCD) or

TC7212A (LED) driver, a 4-1/2 digit display DVM or DPM can

be constructed. Overrange and underrange signals support

automatic range switching and special display blanking/flash-

ing applications.

Microprocessor-based measurement systems are sup-

ported by BUSY, STROBE, and RUN/HOLD control signals.

Remote data acquisition systems with data transfer via UARTs

are also possible. The additional control pins and multiplexed

BCD outputs make the TC7135 the ideal converter for dis-

play or microprocessor-based measurement systems.

TC7135

ORDERING INFORMATION

Temperature

Part No.

Package

Range

TC7135CBU

64-Pin Plastic

0

°C to +70°C

Flat Package

TC7135CLI

28-Pin PLCC

0

°C to +70°C

TC7135CPI

28-Pin Plastic DIP

0

°C to +70°C

TC7135

–5V

V

REF IN

ANALOG

COMMON

UR

OR

STROBE

RUN/HOLD

DGND

POL

CLOCK

BUSY

D1

D2

D3

0.1 µF

0.47 µF

1 µF

ANALOG

GROUND

100 k

Ω

0.1

µF

INPUT

1

2

3

4

5

6

7

8

9

10

11

12

13

14

+5V

28

27

26

25

24

23

22

21

20

19

TC04

+5V

1/4 CD4030

CLOCK IN

+5V

BP

D

D

D

D

1

2

3

4

4-1/2 DIGIT LCD

SEGMENT

D

R

I

V

E

5

31

32

33

34

30

29

28

27

TC7211A

SEG

OUT

OSC

GND

36

+5V

+5V

1

CD4081

1 1615 1412 5 3 4

7 8 13 11 10 9 2 6

CD4054A

OPTIONAL

CAP

35

15

120 Hz = 3 READING/SEC

BACKPLANE

B

B

B

B

3

2

1

0

D4

B8

B4

18

17

16

100 k

Ω

100 k

Ω

6.8 k

Ω

1 µF

INT OUT

AZ IN

BUFF OUT

CREF

CREF

–INPUT

+INPUT

V

D5

B1

B2

+

V

+

2,3,4

6–26

37–40

+

–

+5V

FEATURES

s

Low Roll-Over Error .........................

s

Guaranteed Nonlinearity Error ........

s

Guaranteed Zero Reading for 0V Input

s

True Polarity Indication at Zero for Null Detection

s

Multiplexed BCD Data Output

s

TTL-Compatible Outputs

s

Differential Input

s

Control Signals Permit Interface to UARTs and

s

Auto-Ranging Supported With Overrange and

Underrange Signals

s

Blinking Display Visually Indicates Overrange

Condition

s

Low Input Current ............................................. 1 pA

s

Low Zero Reading Drift ............................... 2

s

Interfaces to TC7211A (LCD) and TC7212A (LED)

Display Drivers

s

Available in DIP and Surface-Mount Packages

TYPICAL 4-1/2 DIGIT DVM WITH LCD

4-1/2 DIGIT ANALOG-TO-DIGITAL CONVERTER

TC7135-10 11/6/96