TelCom Semiconductor Inc TC811CPL, TC811CKW Datasheet

3-1/2 DIGIT A/D CONVERTER WITH HOLD AND DIFFERENTIAL
REFERENCE INPUTS

1

TC811

2

FEATURES

■ Differential Reference Input

■ Display Hold Function

■ Fast Over-Range Recovery, Guaranteed Next

Reading Accuracy

■ Low Temperature Drift Internal

Reference ....................................... 35ppm/°C (Typ)

■ Guaranteed Zero Reading With Zero Input

■ Low Noise..................................................... 15µV

■ High Resolution (0.05%) and Wide Dynamic

Range (72 dB)

■ High Impedance Differential Input

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

10pA Max

■ Direct LCD Drive – No External Components

■ Precision Null Detection with True Polarity at Zero

■ Crystal Clock Oscillator

■ Available in DIP, Compact Flat Package or PLCC

■ Convenient 9V Battery Operation with

Low Power Dissipation (600µA Typical, 1mW
Maximum)

FUNCTIONAL BLOCK DIAGRAM

p-p

TYPICAL APPLICATIONS

■ Thermometry

■ Digital Meters

— Voltage/Current/Power
— pH Measurement
— Capacitance/Inductance
— Fluid Flow Rate/Viscosity
— Humidity
— Position

■ Panel Meters

■ LVDT Indicators

■ Portable Instrumentation

■ Digital Scales

■ Process Monitors

■ Gaussometers

■ Photometers

ORDERING INFORMATION

Temp. Max V

Part No. Package Range Tempco

TC811CKW 44-PQFP 0°C to +70°C 75 ppm/°C
TC811CPL

40-Pin Plastic DIP

0°C to +70°C 75 ppm/°C

REF

3

4

5

C

REF

V

ANALOG

COMMON

V

+

+

V

C

REF

REF

10
µA

31

+
IN

INT

A/Z

32

30

–
IN

DE (+)

INT

ZI & A/Z

DE
(–)DE(+)

AZ & DE (±)

V

DE (–)

–

REF

–

C

REF

33

ZI &
A/Z

V+– 3.0V

26

–

V

TELCOM SEMICONDUCTOR, INC.

V

BUFF

–
+

ZI

–
+

TC811CPL

R

INT

+

V

28

LOW
TEMPCO
V

REF

+

V

TYPICAL SEGMENT OUTPUT

INTERNAL DIGITAL GROUND

C

AZ

29

38

INTEGRATOR

–

+

A/Z

COMPARATOR

40

OSC

1

10pF

+

V

0.5mA
SEGMENT

OUTPUT

2mA

C

INT

V

INT

27343635

TO

DIGITAL

SECTION

+
–

THOUSANDS

TO SWITCH DRIVERS

FROM COMPARATOR OUTPUT
CLOCK

39

22MΩ

470k

OSC

2

20pF

f

OSC

LCD DISPLAY

LCD SEGMENT DRIVERS

7 SEGMENT

DECODE

HUNDREDS

4

INTERNAL DIGITAL GOUND

+

V

7 SEGMENT

DATA LATCH

CONTROL LOGIC

7 SEGMENT

V
= 1V

DECODE

≈70kΩ

TH

1
HLDR

DECODE

TENS UNITS

BACKPLANE

21

200

6.2V

Ω

500

38

V

TEST

26

V

6

7

+

–

8

TC811-7 11/5/96

3-137

TC811

3-1/2 DIGIT A/D CONVERTER WITH HOLD AND

DIFFERENTIAL REFERENCE INPUTS

GENERAL DESCRIPTION

The TC811 is a low power, 3-1/2 digit, LCD display
analog-to-digital converter. This device incorporates both a
display hold feature and differential reference inputs. A
crystal oscillator, which only requires two pins, permits
added features while retaining a 40-pin package. An addi­tional feature is an "Integrator Output Zero" phase which
guarantees rapid input overrange recovery.

The TC811 display hold (HLDR) function can be used to
"freeze" the LCD display. The displayed reading will remain
indefinitely as long as HLDR is held high. Conversions
continue but the output data display latches are not updated.
The TC811 also includes a differential reference for easy
ratiometric measurements. Circuits which use the
7106/26/36 can easily be upgraded to include the hold
function with the TC811.

The TC811 has an improved internal zener reference
voltage circuit which maintains the Analog Common tem­perature drift to 35ppm/°C (typical) and 75ppm/°C (maxi­mum). This represents an improvement of two to four times
over similar 3-1/2 digit converters, eliminating the need for
a costly, space consuming external reference source.

The TC811 limits linearity error to less than one count on
both the 200mV and the 2.00V full-scale ranges. Rollover
error—the difference in readings for equal magnitude but
opposite polarity input signals—is below ±1 count. High
impedance differential inputs offer 1pA leakage currents
and a 1012Ω input impedance. The 15µV
mance guarantees a “rock solid” reading. The Auto Zero
cycle guarantees a zero display readout for a zero volt input.

The single chip CMOS TC811 incorporates all the active
devices for a 3-1/2 digit analog to digital converter to directly
drive an LCD display. Onboard oscillator, precision voltage
reference and display segment and backplane drivers sim-

noise perfor-

p-p

plify system integration, reduce board space requirements
and lower total cost. A low cost, high resolution (0.05%)
indicating meter requires only a TC811, an LCD display, five
resistors, six capacitors, a crystal, and a 9V battery. Com­pact, hand held multimeter designs benefit from the TelCom
Semiconductor small footprint package option.

The TC811 uses a dual slope conversion technique
which will reject interference signals if the converters inte­gration time is set to a multiple of the interference signal
period. This is especially useful in industrial measurement
environments where 50, 60 and 400Hz line frequency sig­nals are present.

ABSOLUTE MAXIMUM RATINGS*

Supply Voltage (V+ to V–)............................................15V

Analog Input voltage (Either Input)1.....................V+ to V

Reference Input Voltage ...................................... V+ to V

Clock Input ......................................................TEST to V

Power Dissipation2 (TA ≤ 70°C)

44-Pin Flat Package .........................................1.00W

40-Pin Plastic DIP.............................................1.23W

Operating Temperature Range

Commercial Package (C) ......................0°C to +70°C

Industrial Package (I)........................– 25°C to +85°C

Storage Temperature Range ................– 65°C to +150°C

Lead Temperature (Soldering, 10 sec) .................+300°C

*Static-sensitive device. Unused devices must be stored in conductive
material. Protect devices from static discharge and static fields. Stresses
above those listed under "Absolute Maximum Ratings" may cause perma­nent damage to the device. These are stress ratings only and functional
operation of the device at these or any other conditions above those
indicated in the operation sections of the specifications is not implied.
Exposure to absolute maximum rating conditions for extended periods may
affect device reliability.

–
–
+

ELECTRICAL CHARACTERISTICS: V

Supply

= 9V, f

= 32.768kHz, and TA = 25°C, unless otherwise noted.

CLOCK

Symbol Parameter Test Conditions Min Typ Max Unit

Input

— Zero Input Reading VIN = 0V – 000.0 ±000.0 +000.0 Digital

VFS = 200mV Reading
— Zero Reading Drift VIN = 0V, 0°C ≤ TA ≤ 70°C — 0.2 1 µV/°C
— Ratiometric Reading VIN = V

NL Linearity Error VFS = 200mV or 2.000V – 1 ±0.2 +1 Counts
E

R

e

N

I

L

CMRR Common-Mode Rejection VCM = ±1V, VIN = 0V, — 50 — µV/V

3-138

Roll Over Error VIN– = VIN+ ≈ 200mV – 1 ±0.2 +1 Counts
Noise VIN = 0V, VFS = 200mV — 15 — µV
Input Leakage Current VIN = 0V — 1 10 pA

VFS = 200mV

REF

, V

= 100mV 999 999/1000 1000 Digital

REF

TELCOM SEMICONDUCTOR, INC.

Reading

P-P

3-1/2 DIGIT A/D CONVERTER WITH HOLD AND
DIFFERENTIAL REFERENCE INPUTS

1

TC811

ELECTRICAL CHARACTERISTICS: V

Supply

= 9V, f

= 32.768kHz, and TA = 25°C, unless otherwise noted.

CLOCK

Symbol Parameter Test Conditions Min Typ Max Unit

TC

SF

Analog Common Section

V

CTC

V

C

Hold Pin Input Section

V

IL

V

IH

LCD Drive Section

V

SD

V

SD

Power Supply

I

SUP

NOTES: 1. Input voltages may exceed supply voltages when input current is limited to 100µA.

Scale Factor Temperature VIN = 199mV, 0°C ≤ TA ≤ 70°C — 1 5 ppm/°C
Coefficient (ext. V

tc = 0ppm)

REF

Analog Common 250KΩ from V+ to Analog Common — — — —
Temperature Coefficient 0°C ≤ T

≤ 70°C————

A

"C" Commercial — 35 75 ppm/°C
"I" Industrial — 35 100 ppm/°C

Analog Common Voltage 250kΩ from V+ to Analog Common 2.7 3.05 3.35 Volts

Input Resistance Pin 1 to Pin 37 — 70 — kΩ
Input Low Voltage Pin 1 — — Test +1.5 V
Input High Voltage Pin 1 V+ – 1.5 — — V

3

LCD Segment Drive Voltage V+ to V– = 9V 4 5 6 V
LCD Backplane Drive Voltage V+ to V– = 9V 4 5 6 V

Power Supply Current VIN = 0V, V+ to V– = 9V — — — —

f

= 16kHz — 70 100 µA

OSC

f

= 48kHz — 90 125 µA

OSC

2. Dissipation rating assumes device is mounted with all leads soldered to a printed circuit board.

3. Backplane drive is in phase with the segment drive for "segment off" 180° out of phase for "segment on." Frequency is 20 times the
conversion rate. Average DC component is less than 50mV.

P-P
P-P

2

3

4

5

PIN CONFIGURATIONS

HLDR

D
C
B

1's

A

F
G
E
D
C
B

10's

A

F
E
D
B

100's

F
E

1000's

AB
POL

(MINUS SIGN)

28

OSC

40

OSC

39
38
37
36
35
34
33
32
31
30
29

27
26
25
24
23
22
21

1

NORMAL PIN

2

CONFIGURATION

1

3

1

4

1

5

1

6

1

7

1

8

1

9

2

10

2
2
2
2
2

3
3

3
3
4

NC = NO INTERNAL CONNECTION

11
12
13
14
15
16

17
18
19
20

TC811CPL

(40-PIN PDIP)

1
2

+

V
TEST

+

V

REF

+

C

REF

–

C

REF

–

V

REF
ANALOG
COMMON

+

V

IN

–

V

IN

C

AZ
V

BUFF

V

INT

–

V
G

10's

2

C

3

100's

A

3

G

3

BP
(BACKPLANE)

NC
NC

TEST

V

NC

OSC
OSC

HLDR

D
C

B

–

+

+

REF

REF

REF

C

C

V

44 43 42 41 39 3840

1
2
3

+

4

5
6

2

7

1

8
9

1

10

1

11

1

12 13 14 15 17 18

1F1G1E1

A

–

REF

COM

V

TC811CKW

(PQFP)

16

D2C2B2A

+

–

IN

V

BUFF35INT

IN

AZ

C

V

37

36

19 20 21 22

2F2E2

–

VVV

34

33

NC

32

G

2

C

31

3

30

A

3

29

G

3

BP

28

POL

27
26

AB

4

E

25

3

F

24

3

23

B

3

3

D

6

7

8

TELCOM SEMICONDUCTOR, INC.

3-139

3-1/2 DIGIT A/D CONVERTER WITH HOLD AND

DIFFERENTIAL REFERENCE INPUTS

TC811

PIN DESCRIPTION

Pin No.
40-Pin Plastic DIP Symbol Description

1 HLDR Hold pin, logic 1 holds present display reading.
2D
3C
4B
5A
6F
7G
8E
9D
10 C
11 B
12 A
13 F
14 E
15 D
16 B
17 F
18 E
19 AB

1
1
1
1
1
1
1
2
2
2
2
2
2
3
3
3
3

4

20 POL Activates the negative polarity display.
21 BP Backplane drive output.
22 G
23 A
24 C
25 G
26 V
27 V
28 V
29 C

3
3
3
2

–

INT

BUFF

AZ

30 VIN– Analog input low.
31 VIN+ Analog input high.
32 COM Analog Common: Internal zero reference.
33 V
34 C
35 C
36 V

– Reference input low.

REF

– Negative connection for reference capacitor.

REF

+ Positive connection for reference capacitor.

REF

+ Reference input high.

REF

37 TEST All LCD segment test when pulled high (V+).
38 V
39 OSC
40 OSC

+

2
1

Activates the D section of the units display.
Activates the C section of the units display.
Activates the B section of the units display.
Activates the A section of the units display.
Activates the F section of the units display.
Activates the G section of the units display.
Activates the E section of the units display.
Activates the D section of the tens display.
Activates the C section of the tens display.
Activates the B section of the tens display.
Activates the A section of the tens display.
Activates the F section of the tens display.
Activates the E section of the tens display.
Activates the D section of the hundreds display.
Activates the B section of the hundreds display.
Activates the F section of the hundreds display.
Activates the E section of the hundreds display.
Activates both halves of the 1 in the thousands display.

Activates the G section of the hundreds display.
Activates the A section of the hundreds display.
Activates the C section of the hundreds display.
Activates the G section of the tens display.
Negative power supply voltage.
Integrator output, connection for C
Buffer output, connection for R
Integrator input, connection for CAZ.

Positive power supply voltage.
Crystal oscillator output.
Crystal oscillator input.

INT

.

INT

.

3-140

TELCOM SEMICONDUCTOR, INC.