TelCom Semiconductor Inc TC7135CLI, TC7135CBU, TC7135CPI Datasheet

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

1

TC7135

FEATURES

■ Low Roll-Over Error ......................... ±1 Count Max

■ Guaranteed Nonlinearity Error ........ ±1 Count Max

■ Guaranteed Zero Reading for 0V Input

■ True Polarity Indication at Zero for Null Detection

■ Multiplexed BCD Data Output

■ TTL-Compatible Outputs

■ Differential Input

■ Control Signals Permit Interface to UARTs and

µProcessors

■ Auto-Ranging Supported With Overrange and

Underrange Signals

■ Blinking Display Visually Indicates Overrange

Condition

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

■ Low Zero Reading Drift ............................... 2 µV/°C

■ Interfaces to TC7211A (LCD) and TC7212A (LED)

Display Drivers

■ Available in DIP and Surface-Mount Packages

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/flash­ing applications.

Microprocessor-based measurement systems are sup­ported 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 dis­play or microprocessor-based measurement systems.

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

2

3

4

5

TYPICAL 4-1/2 DIGIT DVM WITH LCD

6.8 kΩ

+5V

0.1 µF

TC04

ANALOG

GROUND

1 µF

100 kΩ

0.1
µF

INPUT

TELCOM SEMICONDUCTOR, INC.

–5V

100 kΩ

0.47 µF
1 µF

100 kΩ

+5V

1
2
3
4
5
6
7
8

9
10
11
12
13
14

V
REF IN

ANALOG
COMMON
INT OUT

AZ IN
BUFF OUT

–

C

REF
+

C

REF

–INPUT
+INPUT

+

V
D5

TC7135

B1
B2

STROBE

RUN/HOLD

CLOCK

UR
OR

DGND

POL

BUSY

D1
D2
D3
D4
B8
B4

+5V

28
27
26
25
24
23
22
21
20
19
18
17
16
15

TC7135CPI 28-Pin Plastic DIP 0°C to +70°C

4-1/2 DIGIT LCD

1161514125 3 4

CD4054A

7 8 131110 9 2 6

120 Hz = 3 READING/SEC

CLOCK IN

1/4 CD4030

+5V

CD4081

BACKPLANE

5

BP

31

1

D

32

2

D

33

3

D

34

4

D

30

B

3

29

B

2

28

B

1

27

B

0

SEGMENT

+5V

1

+

V

TC7211A

SEG
OUT

OSC

GND

D
R

I
V
E

2,3,4
6–26
37–40

36

+5V

OPTIONAL
CAP

35

6

7

8

TC7135-10 11/6/96

3-113

TC7135

4-1/2 DIGIT

ANALOG-TO-DIGITAL CONVERTER

ABSOLUTE MAXIMUM RATINGS* (Note 1)

Positive Supply Voltage ............................................. +6V

Negative Supply Voltage.............................................–9V

Analog Input Voltage (Pin 9 or 10) ......... V+ to V– (Note 2)

Reference Input Voltage (Pin 2)........................... V+ to V

Clock Input Voltage ..............................................0V to V

Operating Temperature Range ....................0°C to +70°C

Storage Temperature Range .................–65°C to +160°C

ELECTRICAL CHARACTERISTICS: T

= +25°C, f

A

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

Package Power Dissipation (TA ≤ 70°C)

Plastic DIP ........................................................1.14W

PLCC ................................................................1.00W

–
+

Plastic Flat Package .........................................1.14W

*Static-sensitive device. Unused devices must be stored in conductive
material to protect them 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 operational sections of the specifications is not implied.

= 120 kHz, V+ = +5V, V– = –5V (Figure 1)

CLOCK

Symbol Parameter Test Conditions Min Typ Max Unit

Analog

Display Reading With Notes 2 and 3 –0.0000 ±0.0000 +0.0000 Display
Zero Volt Input Reading

TC

Z

TC

FS

NL Nonlinearity Error Note 6 — 0.5 1 Count
DNL Differential Linearity Error Note 6 — 0.01 — LSB

±FSE ± Full-Scale Symmetry –VIN = +V

I

IN

V

N

Digital

I

IL

I

IH

V

OL

V

OH

f

CLK

Power Supply

+

V

–

V

+

I

–

I
PD Power Dissipation f

NOTES: 1. Limit input current to under 100µA if input

Zero Reading Temperature VIN = 0V — 0.5 2 µV/°C
Coefficient Note 4

Full-Scale Temperature VIN = 2V — — 5 ppm/°C
Coefficient Notes 4 and 5

Display Reading in VIN = V

REF

+0.9996 +0.9999 +1.0000 Display

Ratiometric Operation Note 2 Reading

IN

— 0.5 1 Count

Error (Roll-Over Error) Note 7
Input Leakage Current Note 3 — 1 10 pA
Noise Peak-to-Peak Value Not — 15 — µV

Exceeded 95% of Time

Input Low Current VIN = 0V — 10 100 µA
Input High Current VIN = +5V — 0.08 10 µA
Output Low Voltage IOL = 1.6 mA — 0.2 0.4 V
Output High Voltage

B

, B2, B4, B8, D1–D

1

5

Busy, Polarity, Overrange, I

IOH = 1 mA 2.4 4.4 5 V

= 10 µA 4.9 4.99 5 V

OH

Underrange, Strobe

Clock Frequency Note 8 0 120 1200 kHz

Positive Supply Voltage 4 5 6 V
Negative Supply Voltage –3 –5 –8 V
Positive Supply Current f
Negative Supply Current f

voltages exceed supply voltage.

2. Full-scale voltage = 2V.

3. VIN = 0V.

4. 0°C ≤ TA ≤ +70°C.

= 0 Hz — 1 3 mA

CLK

= 0 Hz — 0.7 3 mA

CLK

= 0 Hz — 8.5 30 mW

CLK

5. External reference temperature coefficient less than 0.01 ppm/°C.

6. –2V ≤ VIN ≤ +2V. Error of reading from best fit straight line.

7. |VIN| = 1.9959.

8. Specification related to clock frequency range over which the
TC7135 correctly performs its various functions. Increased errors
result at higher operating frequencies.

P-P

3-114

TELCOM SEMICONDUCTOR, INC.

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

PIN CONFIGURATIONS

NC
NC
NC
NC
NC
NC

OVERRANGE

UNDERRANGE

NC

V

REF IN

ANALOG COM

NC
NC
NC
NC

NCNCNC

NC

63 61 60 59 58 57 56 55 545352 51 50 4964

62

1

●

2
3
4
5
6
7
8
9

–

10
11
12
13
14
15
16

17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

NC

INT OUT

NOTES: 1. NC = No internal connection.

NC

AZ IN

STROBE

RUN/HOLD

TC7135CBU

(NOTES 1)

NC

–

BUFF OUT

DGND

(PFP)

REF

C

POL

NC

NC

NC

+

CLOCK IN

BUSYD2D1

NC

REF

C

–INPUT

NC

NC

NC

NC

+INPUT

1

TC7135

2

–

V

1

NC

48

NC

47

NC

46

NC

45

D3

44

D4

43

B8

42

B4

41

B2

40

NC

39

B1

38

D5

37

NC

36

NC

35

NC

34

NC

33

NC

32

+

V

REF IN

ANALOG

INT OUT

BUFF OUT

–

+

(MSD) D5

(LSB) B1

AZ IN

BUFF OUT

REF CAP
REF CAP

–

INPUT

+

INPUT

COM

AZ IN

–

C

REF
+

C

REF

INPUT
INPUT

V

B2

–
+

+

V

2
3
4
5
6
7

TC7135CPI

8
9

10

+

11
12
13
14

5
6
7
8

9
10
11

(PDIP)

INT OUT

ANALOG

COM

REF IN

4 3 2 1 27 2628

TC7135CLI

(PLCC)

12 13 14 15 17 18

B2

D5

B1

(LSB)

(MSD)

–

URORSTROBE

V

16

B4

(MSB)

B8

28
27
26
25
24
23
22
21
20
19
18
17

16

15

D4

UNDERRANGE

OVERRANGE
STROBE

RUN/HOLD
DIGTAL GND
POLARITY
CLOCK IN
BUSY
D1 (LSD)
D2
D3
D4
B8 (MSB)
B4

25

RUN/HOLD

24

DIGTAL GND

23

POLARITY

22

CLOCK IN

21

BUSY

20

D1 (LSD)

19

D2

D3

3

4

5

6

TELCOM SEMICONDUCTOR, INC.

7

8

3-115

TC7135

4-1/2 DIGIT

ANALOG-TO-DIGITAL CONVERTER

SET V
V

REF

REF
IN

= 1V

100 kΩ

ANALOG GND

0.47
µF

100 kΩ

SIGNAL
INPUT

+

5V

100
kΩ

LOGIC

INPUT

0.1 µF

–5V

1

–

V

2

REF IN

3

ANALOG
COMMON

4

1 µF

5
6

7
8
9

10
11
12
13
14

INT OUT
AZ IN

BUFF OUT

–

C

REF

+

C

REF

–

INPUT

+

INPUT

+

V
D5 (MSD)

B1 (LSB)
B2

1 µF

Figure 1. Test Circuit

+

V

UNDERRANGE

OVERRANGE

STROBE

RUN/HOLD

DIGTAL GND

POLARITY

CLOCK IN

(LSD) D1

TC7135

(MSB) B8

BUSY

D2
D3
D4

B4

28
27

26
25
24
23

22
21
20
19
18

17
16
15

BUFFER

CLOCK
INPUT
120 kHz

+

IN

REF

IN

ANALOG
COM

–

IN

+

IN

REF

IN

ANALOG
COM

–

IN

SW

SW

SW

SW

SW

SW

SW

SW

ANALOG

SW

C

REF

SW

INPUT BUFFER

+
RI

–

RI

SW

1

+

–

SWIZSW

SW

Z

R

Z

INT

C

INT

C

SZ

–

+

INTEGRATOR

SWITCH OPEN
SWITCH CLOSED

COMPARATOR

+

–

TO
DIGITAL
SECTION

I

–

SW

RI

R

Z

+

SW

RI

I

Figure 3B. System Zero Phase

ANALOG

SW

C

REF

SW

INPUT BUFFER

+
RI

–

RI

SW

1

+

–

SWIZSW

SW

Z

R

INT

Z

C

INT

C

SZ

–

+

INTEGRATOR

SWITCH OPEN

SWITCH CLOSED

COMPARATOR

+

–

TO
DIGITAL
SECTION

I

–

SW

RI

R

Z

+

SW

RI

I

+

IN

REF

IN

ANALOG
COM

–

IN

3-116

SW

SW

SW

SW

Figure 2. Digital Logic Input

ANALOG

SW

C

REF

SW

INPUT BUFFER

+
RI

–

RI

SW

1

+

–

SWIZSW

SW

Z

I

–

SW

RI

R

Z

+

SW

RI

I

Figure 3A. Internal Analog Switches

R

INT

Z

C

INT

C

SZ

–

+

INTEGRATOR

COMPARATOR

+

–

TO
DIGITAL
SECTION

+

IN

REF

IN

ANALOG
COM

–

IN

Figure 3C. Input Signal Integration Phase

ANALOG

SW

C

REF

SW

INPUT BUFFER

+
RI

–

RI

SW

1

+

–

SWIZSW

SW

Z

R

INT

Z

C

INT

C

SZ

–

+

INTEGRATOR

SWITCH OPEN
SWITCH CLOSED

SW

SW

SW

SW

I

–

SW

RI

R

Z

+

SW

RI

I

Figure 3D. Reference Voltage Integration Phase

TELCOM SEMICONDUCTOR, INC.

COMPARATOR

+

–

TO
DIGITAL
SECTION