MICROCHIP TC7106, TC7106A, TC7107, TC7107A Technical data

TC7106/A/TC7107/A

3-1/2 Digit Analog-to-Digital Converters

Features

• Internal Reference with LowTemperature Drift

- TC7106/7: 80ppm/°C Typical

- TC7106A/7A: 20ppm/°C Typical

• Drives LCD (TC7106) or LED (TC7107) Display Directly

• Zero Reading with Zero Input

• Low Noise for Stable Display

• Auto-Zero Cycle Eliminates Need for Zero Adjustment

• True Polarity Indication for Precision Null Applications

• Convenient 9V Battery Operation (TC7106A)

• High Impedance CMOS Differential Inputs: 10

• Differential R eference Inputs Simplify Ratiometric Measurements

• Low Power Operation: 10mW

12

Applications

• Thermometry

• Bridge Readouts:StrainGauges, Load Cel ls, Null Detectors

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

• Digital Scales, Process Monitors

• PortableInstrumentation

General Description

The TC7106A and TC7107A 3-1/2 digit direct display drive analog-to-digital converters allow existing 7106/ 7107 based systems to be upgraded. Each device has a precision reference with a 20ppm/°C max temperature coefficient.Thisrepresentsa4 to 7 times improvement over similar 3-1/2 digit converters. Existing 7106 and 7107 based systems may be upgraded without changing external passive component values. The TC7107A drives common anode light emitting diode (LED) displays directly with 8mA per segment. A low cost, high resolution indicating meter requires only a display, four resistors, and four capacitors.The TC7106A low power drain and 9V battery operation

Ω

make i t suitable for portable applications. The TC7106A/TC7107A reduces linearity error to less

than1 count. Rollovererror–thedifference in readings forequalmagnitude,butoppositepolarity input signals, is below ±1 count. High impedance differential inputs offer 1pA leakage current and a 10 ance. The differentialreferenceinput allows ratiometric measurements for ohms or bridge transducer measurements.The15µV “rock solid” reading. The auto-zero cycle ensures a zero display reading with a zero volts input.

noise performanceensuresa

P–P

12

Ω input imped-

Device Selection Table

Package

Code

CPI 40-Pin PDIP Normal 0°Cto+70°C

IPL 40-Pin PDIP Normal -25°Cto+85°C

IJL 40-PinCERDIP Normal -25°Cto+85°C

CKW 44-PinPQFP FormedLeads 0°Cto+70°C

CLW 44-Pin PLCC — 0°Cto+70°C



2002 Microchip TechnologyInc. DS21455B-page 1

Package Pin Layout

Temperature

Range

TC7106/A/TC7107/A

D

Package Type

1

V+

Normal Pin

D

2

Configuration

1

C

3

1

B

4

1

A

AB

POL

1

F

1

G

1

E

1

D

2

10

C

2

B

11

2

A

12

2

F

13

2

E

14

2

15

D

3

B

16

3

F

17

3

18

E

3

19

4

20

5

6

7

8

TC7106ACPL

9

TC7107AIPL

1's

10's

100's

1000's

(Minus Sign) (Minus Sign)

40

OSC1

39

OSC2

38

OSC3

37

TEST

36

V

35

V

C

34

C

33

ANALOG

32

COMMON

31

V

30

C

29

28

V

27

V

26

V-

25

G

24

C

23

A

22

G

21

BP/GND (7106A/7107A)

REF

IN

AZ

BUFF

INT

2

3

+

-

+

-

+

-

100's

OSC1

OSC2

OSC3

TEST

V

REF

V

REF

C

REF

C

REF

ANALOG

COMMON

V

C

V

BUFF

V

100's

BP/GND

(7106A/7107A)

+

-

+

-

+

10

IN

-

11

IN

12

AZ

13

14

INT

15

V-

G

16

2

C

17

3

A

18

3

G

19

3

20

40-Pin CERDIP40-Pin PDIP

1

Reverse

2

Configuration

3

4

5

6

7

8

TC7106AIJL

9

TC7107AIJL

40

V+

D

39

1

C

38

1

B

37

1

A

36

1's

1

F

35

1

G

34

1

E

33

1

32

D

2

31

C

2

B

30

2

10's

A

29

2

F

28

2

E

27

2

26

D

3

B

25

3

100's

F

24

3

23

E

3

22

AB

1000's

4

21

POL

44-Pin PLCC 44-Pin PQFP

1

A

B1C1D1V+NCOSC1

7

F

1

8

G

1

9

E

1

10

D

2

11

C

2

12

NC

13

B

2

14

A

2

15

F

2

16

E

2

17

D

3

TC7106ACLW TC7107ACLW

18 19 20 21 22 23 24 25 26 27 28

3F3

3AB4

B

E

POL

OSC2

44 43 42 41 40

123456

3A3C3G2

G

NC

BP/GND

OSC3

TEST

REF HI

39

38

37

36

35

34

33

32

31

30

29

REF LO

C

REF

C

REF

COMMON

IN HI

NC

IN LO

A/Z

BUFF

INT

V-

TEST

OSC3

OSC2

OSC1

1

NC

2

NC

3

4

5

NC

6

7

8

V+

9

D

1

10

C

1

11

B

1

12 13 14 15 16 17 18 19 20 21 22

REFCREF

REF HI

REF LO

C

COM

IN HI

394041424344

TC7106ACKW TC7107ACKW

1F1

1E1D2C2B2A2F2E2D3

A

G

IN LO

A/Z

BUFF

INT

38 37 36 35 34

V-

NC

33

G

32

2

C

31

3

A

30

3

G

29

3

BP/GN

28

POL

27

26

AB

4

25

E

3

24

F

3

23

B

3

DS21455B-page 2



2002 Microchip TechnologyInc.

Typical Application

r

TC7106/A/TC7107/A

+

Analog

Input

–

1MΩ

0.01µF

47kΩ

0.22µF

0.47µF

0.1µF

34

+

REF

31

+

V

IN

30

V

-

IN

ANALOG

32

COMMON

TC7106/A

28

29

27

TC7107/A

V

BUFF

C

AZ

V

INT

39 38 40

R

OSC

100kΩ

33

C

REF

C

100pF

-C

OSC

2 - 19

22 - 25

POL

BP

V+

V

REF

V

REF

V-

OSC1OSC3OSC2

Segment Drive

20

Minus Sign

21

1

V

REF

36

+

100mV

35

-

26

3 Conversions/Sec 200mV Full Scale

LCD Display (TC7106/A) o

Common Node w/ LED

Display (TC7107/A)

Backplane Drive

24kΩ

+

1kΩ

To Analog Common (Pin 32)

9V



2002 Microchip TechnologyInc. DS21455B-page 3

TC7106/A/TC7107/A

1.0 ELECTRICAL CHARACTERISTICS

Absolute Maximum Ratings* TC7106A

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

Analog Input Voltage(either Input) (Note 1) ... V+ to V-

Reference Input Voltage (either Input) ............V+ to V-

Clock Input ................................................... Test to V+

Package Power Dissipation (T

40-Pin CERDIP .......................................2.29W

40-Pin PDIP ............................................1.23W

44-Pin PLCC ...........................................1.23W

44-Pin PQFP ...........................................1.00W

Operating Temperature Range:

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

I (Industrial) Devices ................-25°C to +85°C

StorageTemperature Range..............-65°C t o +150°C

TC7107A

Supply Voltage (V+) ...............................................+6V

Supply Voltage (V-)..................................................-9V

Analog Input Voltage(either Input) (Note 1) ... V+ to V-

Reference Input Voltage (either Input) ............V+ to V-

Clock Input ..................................................GND to V+

Package Power Dissipation (T

40-Pin CERDip........................................2.29W

40-Pin PDIP ............................................1.23W

44-Pin PLCC ...........................................1.23W

44-Pin PQFP ...........................................1.00W

Operating Temperature Range:

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

I (Industrial) Devices ................-25°C to +85°C

StorageTemperature Range..............-65°C t o +150°C

≤ 70°C) (Note 2):

A

≤ 70°C) (Note 2):

A

*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 affectdevice reliability.

TC7106/A AND TC7107/A ELECTRICAL SPECIFICATIONS

Electrical Characteristics: Unless otherwise noted, specifications apply to both the TC7106/A and TC7107/A at TA=25°C,

f

= 48kHz. Partsare testedin the circuitof the Typical Operating Circuit.

CLOCK

Symbol Parameter Min Typ Max Unit Test Conditions

Z

IR

R/O Rollover Error (Difference in Readingfor

Note 1: Input voltages may exceed the supply voltages, provided the input current is limited to ±100µA.

DS21455B-page 4

Zero Input Reading -000.0 ±000.0 +000.0 Digital

Reading

Ratiometric Reading 999 999/1000 1000 Digital

Reading

-1 ±0.2 +1 Counts V Equal Positive and Negative Reading Near Full Scale)

Linearity (Max. Deviation from Best Straight Line Fit)

2: Dissipationrating assumes device is mounted with all leads solderedto printedcircuit board. 3: Refer to “Differential Input” discussion. 4: Backplane drive is in phasewithsegment drive for “OFF” segment,180°out of phase for “ON” segment.

Frequency is 20 timesconversion rate. Average DC component is less than 50mV.

-1 ±0.2 +1 Counts Full Scale = 200mV or

VIN=0.0V Full Scale = 200.0mV

V

IN=VREF

V

=100mV

REF

-=+VIN+ ≅ 200mV

IN

Full Scale = 2.000V



2002 Microchip TechnologyInc.

TC7106/A/TC7107/A

TC7106/A AND TC7107/A ELECTRICAL SPECIFICATIONS (CONTINUED)

Electrical Characteristics: Unless otherwise noted, specifications apply to both the TC7106/A and TC7107/A at TA=25°C,

f

= 48kHz. Partsare testedin the circuitof the Typical Operating Circuit.

CLOCK

Symbol Parameter Min Typ Max Unit Test Conditions

CMRR Common Mode Rejection Ratio (Note 3) —50—µV/V VCM=±1V,VIN=0V,

e

N

I

L

Noise (Peak to Peak Value not Exceeded 95% of Time)

Leakage Current at Input — 1 10 pA VIN=0V

—15—µVVIN=0V

Zero Reading Drift — 0.2 1 µV/°C V

—1.02µV/°C V

TC

Scale FactorTemperatureCoefficient — 1 5 ppm/°C VIN=199.0mV,

SF

——20ppm/°CV

I

DD

V

C

V

CTC

SupplyCurrent (Does not include LED Current For TC7107/A)

AnalogCommonVoltage (with Respectto PositiveSupply)

T emperature Coefficient of Analog

—0.81.8mAV

2.7 3.05 3.35 V 25kΩ BetweenCommonand

————25kΩ BetweenCommonand

Common (withRespectto Positive Supply)

7106/7/A

7106/7

V

CTC

V

SD

T emperature Coefficient of Analog Common (withRespectto Positive Supply)

TC7106A ONLY Peak to Peak

— — 75 ppm/°C 0°C≤ TA≤ +70°C

456VV+toV-=9V

20 80

50 —

ppm/°C ppm/°C

SegmentDriveVoltage

V

BD

TC7106A ONLY Peak to Peak Backplane Drive Voltage

TC7107A ONLY

456VV+toV-=9V

58.0—mAV+=5.0V

SegmentSinking Current (Except Pin 19) TC7107A ONLY

10 16 — mA V+ = 5.0V

SegmentSinking Current (Pin19)

Note 1: Input voltages may exceed the supply voltages, provided the input current is limited to ±100µA.

2: Dissipationrating assumes device is mounted with all leads solderedto printedcircuit board. 3: Refer to “Differential Input” discussion. 4: Backplane drive is in phasewithsegment drive for “OFF” segment,180°out of phase for “ON” segment.

Frequency is 20 timesconversion rate. Average DC component is less than 50mV.

Full Scale = 200.0mV

Full Scale - 200.0mV

=0V

IN

“C” Device = 0°C to +70°C

=0V

IN

“I” Device= -25°C to +85°C

“C” Device = 0°C to +70°C (Ext.Ref = 0ppm°C)

=199.0mV

IN

“I” Device= -25°C to +85°C

=0.8

IN

Positive Supply

Positive Supply 0°C ≤ T

≤ +70°C

A

(“C” Commercial Temperature Range Devices)

(“I” Industrial Temperature Range Devices)

(Note 4)

Segment Voltage = 3V



2002 Microchip TechnologyInc. DS21455B-page 5

TC7106/A/TC7107/A

2.0 PIN DESCRIPTIONS

The descriptions of the pins are listed in Table 2-1.

TABLE 2-1: PIN FUNCTION TABLE

Pin Number

(40-Pin PDIP)

Normal

1 (40) V+ Positive supply voltage. 2(39)D 3(38)C 4(37)B 5(36)A 6(35)F 7(34)G 8(33)E

9(32)D 10 (31) C 11 (30) B 12 (29) A 13 (28) F 14 (27) E 15 (26) D 16 (25) B 17 (24) F 18 (23) E 19 (22) AB 20 (21) POL Activates the negativepolarity display. 21 (20) BP/GND LCD Backplane drive output (TC7106A). Digital Ground (TC7107A). 22 (19) G 23 (18) A 24 (17) C 25 (16) G 26 (15) V- Negative power supply voltage. 27 (14) V

28 (13) V

29 (12) C

30 (11) V 31 (10) V 32 (9) ANALOG

33 (8) C 34 (7) C

35 (6) V

Pin No.

(40-Pin PDIP)

(Reversed

Symbol Description

Activates the D section of the units display.

1

Activates the C section of the units display.

1

Activates the B section of t he units display.

1

Activates the A section of t he units display.

1

Activates the F sectionof the units display.

1

Activates the G section of the units display.

1

Activates the E section of t he units display.

1

Activates the D section of the tens display.

2

Activates the C section of the tens display.

2

Activates the B section of the tens display.

2

Activates the A section of the tens display.

2

Activates the F section of the tensdisplay.

2

Activates the E section of the tens display.

2

Activates the D section of the hundreds display.

3

Activates the B section of the hundreds display.

3

Activates the F section of the hundreds display.

3

Activates the E section of the hundreds display.

3

Activates both halves of the 1 in the thousands display.

4

Activates the G section of the hundreds display.

3

Activates the A section of the hundreds display.

3

Activates the C section of the hundreds display.

3

Activates the G section of the tens display.

2

Integrator output. Connection point for integration capacitor. See INTEGRATING

INT

CAPACITOR section for more details.

BUFF

Integration resistor connection. Use a 47kΩ resistor fora 200mV fullscalerange and a47kΩ resistor for 2V full scale range.

The size of the auto-zero capacitor influences system noise.Usea 0.47µF capacitor

AZ

for 200mV full scale,anda 0.047µF capacitor for 2V full scale. See Section 7.1 on Auto-Zero Capacitor for more details.

- The analogLOW input is connected to this pin.

IN

+ The analog HIGH input signal is connected to this pin.

IN

This pin is primarilyusedto set the Analog Commonmode voltage for battery opera-

COMMON

tion or in systems where the input signal is referenced to the power supply. It also actsasareferencevoltage source.See Section 8.3 on ANALOGCOMMONfor more details.

- See Pin 34.

REF

+A0.1µF capacitor is used in mostapplications. If a largeCommonmodevoltage

REF

exists (for example, the V used, a 1µF capacitoris recommended and will hold the rollover errorto 0.5 count.

- See Pin 36.

REF

- pin is not at analog common), and a 200mV scale is

IN

DS21455B-page 6



2002 Microchip TechnologyInc.

TC7106/A/TC7107/A

TABLE 2-1: PIN FUNCTION TABLE (CONTINUED)

Pin Number

(40-Pin PDIP)

Normal

36 (5) V

37 (4) TEST Lamp test. When pulled HIGH (to V+) all segments willbe turnedon and the display

38 (3) OSC3 See Pin 40. 39 (2) OSC2 See Pin 40. 40 (1) OSC1 Pins 40, 39, 38 make up the oscillator section. For a 48kHz clock (3 readings per

Pin No.

(40-Pin PDIP)

(Reversed

Symbol Description

+ Theanalog inputrequired to generate a fullscaleoutput (1999counts). Place100mV

REF

between Pins 35 and 36 for 199.9mVfull scale. Place1V between Pins 35 and 36 for 2V full scale. See paragraph on Reference Voltage.

shouldread -1888. It may also be used as a negativesupplyfor externallygenerated decimal points. See paragraph under TEST for additionalinformation.

section), connect Pin 40 to the junction of a 100kΩ resistor and a 100pF capacitor. The 100kΩ resistoristiedto Pin 39 and the 100pFcapacitor is tied to Pin 38.



2002 Microchip TechnologyInc. DS21455B-page 7

TC7106/A/TC7107/A

q

y

3.0 DETAILED DESCRIPTION

(All Pin designations refer to 40-Pin PDIP.)

3.1 Dual S lope Conversion Principles

The TC7106Aand TC7107A are dual slope,integrating analog-to-digital converters. An understanding of the dualslopeconversiontechnique will aid infollowingthe detailed operation theory.

The conventional dual slope converter measurement cycle has two distinct phases:

• Input Signal Integration

• Reference VoltageIntegration (De-integration) The input signal being converted is integrated for a

fixed time period (T clock pulses. An opposite polarity constant reference voltage is then integrated until the integrator output voltage returns to zero. The reference integration time is directly proportional to the input signal (T Figure 3-1.

FIGURE 3-1: BASIC DUAL SLOPE

Analog

Input

Signal

). Time is measured by counting

SI

). See

RI

CONVERTER

C

Integrator

–

+

Comparator

–

+

For a constant VIN:

EQUATION 3-2:

T

VIN=V

RI

R

T

SI

The dual slope converter accuracy is unrelated to the integrating resistor and capacitor values as long as they are stable during a measurement cycle. An inherent benefit is noise immunity. Noise spikes are integrated or averaged to zero during the integration periods.IntegratingADCs areimmunetothe largeconversion errors that plague successive approximation converters in high noise environments. Interfering signals with frequency components at multiples of the averaging period will be attenuated. Integrating ADCs commonlyoperatewiththesignalintegrationperiodset to a multiple of the 50/60Hz power line period (see Figure 3-2).

FIGURE 3-2: NORM AL MODE

REJECTION OF DUAL SLOPE CONVERTER

30

20

+/–

REF

Voltage

Output

Integrator

Fixed

Signal

Integrate

Time

Switch

Driver

Polarity Control

DISPLAY

Variable Reference Integrate Time

Phase Control

≈ V

V

IN

REF

VIN ≈ 1/2 V

REF

Control

Logic

Clock

Counter

In a simple dual slope converter, a complete c onversion requires the integrator output to “ramp-up” and “ramp-down.” A simple mathematical equation relates the input signal, referencevoltage and integration time.

EQUATION 3-1:

T

Where:

V

R

T

SI

T

RI

1

SI

VIN(t)dt=

∫

RC

0

= Reference voltage = Signal integrationtime (fixed) = Referencevoltageintegration time (variable).

V

RTRI

RC

10

Normal Mode Rejection (dB)

0

0.1/T 1/T 10/T

T = Measured Period

Input Fre

uenc

DS21455B-page 8



2002 Microchip TechnologyInc.