TC811

TC811-7 11/5/96

© 2001 Microchip Technology Inc.

DS21472A

TC811CPL

THOUSANDS

HUNDREDS

TENS

UNITS

4

39

OSC

V

TEST

TO SWITCH DRIVERS

FROM COMPARATOR OUTPUT

CLOCK

7 SEGMENT

DECODE

40

2

OSC1

CONTROL LOGIC

26

500

Ω

DATA LATCH

+

BUFF

CREF

–

RINT

V

+

CAZ

VINT

28

29

27

34

36

35

10

µA

31

ZI & A/Z

INT

AZ & DE (

±)

32

INT

26

INTEGRATOR

TO

DIGITAL

SECTION

DE (+)

DE

(–)

DE

(+)

DE (–)

ANALOG

COMMON

C REF

+

V IN

+

V IN

–

V

CINT

VREF

+

VREF

–

ZI &

A/Z

CREF

+

33

+

–

LCD SEGMENT DRIVERS

200

BACKPLANE

fOSC

V

–

VTH

= 1V

V

–

+

–

INTERNAL DIGITAL GOUND

LOW

TEMPCO

VREF

COMPARATOR

–

A/Z

ZI

V+– 3.0V

38

470k

10pF

7 SEGMENT

DECODE

7 SEGMENT

DECODE

21

TYPICAL SEGMENT OUTPUT

INTERNAL DIGITAL GROUND

SEGMENT

OUTPUT

V

+

0.5mA

2mA

6.2V

LCD DISPLAY

+

–

38

20pF

V

+

V

+

22M

Ω

HLDR

≈70kΩ

A/Z

30

1

FUNCTIONAL BLOCK DIAGRAM

ORDERING INFORMATION

Temp.

Part No.

Package

Range

Temp. Co.

TC811CKW

44-Pin PQFP

0

°C to +70°C 75 ppm/°C

TC811CPL

40-Pin Plastic DIP 0

°C to +70°C 75 ppm/°C

3-1/2 Digit Analog-To-Digital Converter with Hold and

Differential Reference Inputs

FEATURES

s

Differential Reference Input

s

Display Hold Function

s

Fast Over-Range Recovery, Guaranteed Next

Reading Accuracy

s

Low Temperature Drift Internal

Reference ....................................... 35ppm/

s

Guaranteed Zero Reading With Zero Input

s

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

s

High Resolution (0.05%) and Wide Dynamic

Range (72 dB)

s

High Impedance Differential Input

s

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

10pA Max

s

Direct LCD Drive -No External Components

s

Precision Null Detection with True Polarity at Zero

s

Crystal Clock Oscillator

s

Available in DIP, Compact Flat Package or PLCC

s

Convenient 9V Battery Operation with

Low Power Dissipation (600

Maximum)

TYPICAL APPLICATIONS

s

Thermometry

s

Digital Meters

— Voltage/Current/Power

— pH Measurement

— Capacitance/Inductance

— Fluid Flow Rate/Viscosity

— Humidity

— Position

s

Panel Meters

s

LVDT Indicators

s

Portable Instrumentation

s

Digital Scales

s

Process Monitors

s

Gaussometers

s

Photometers