21455b.book

2002 Microchip Technology Inc.

DS21455B-page 1

TC7106/A/TC7107/A

Features

• Internal Reference with Low Temperature 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

Ω

• Differential Reference Inputs Simplify Ratiometric

Measurements

• Low Power Operation: 10mW

Applications

• Thermometry

• Bridge Readouts: Strain Gauges, Load Cells, Null

Detectors

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

• Digital Scales, Process Monitors

• Portable Instrumentation

Device Selection Table

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 tempera-

ture coefficient. This represents a 4 to 7 times improve-

ment 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

make it suitable for portable applications.

The TC7106A/TC7107A reduces linearity error to less

than 1 count. 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 current and a 10

Ω

input imped-

ance. The differential reference input allows ratiometric

measurements for ohms or bridge transducer mea-

surements. The 15

P–P

noise performance ensures a

“rock solid” reading. The auto-zero cycle ensures a

zero display reading with a zero volts input.

Package

Code

Package

Pin Layout

Temperature

Range

CPI

40-Pin PDIP

Normal

C to +70

IPL

40-Pin PDIP

Normal

-25

C to +85

IJL

40-Pin CERDIP

Normal

-25

C to +85

CKW

44-Pin PQFP

Formed Leads

C to +70

CLW

44-Pin PLCC

—

C to +70

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

TC7106/A/TC7107/A

DS21455B-page 2

2002 Microchip Technology Inc.

Package Type

TC7106ACPL

TC7107AIPL

44-Pin PLCC

44-Pin PQFP

40-Pin CERDIP

40-Pin PDIP

OSC1

TEST

REF

ANALOG

COMMON

V+

Normal Pin

Configuration

(Minus Sign)

10's

100's

1000's

(7106A/7107A)

100's

OSC2

OSC3

REF

BUFF

INT

V-

BP/GND

POL

TC7106AIJL

TC7107AIJL

100's

1000's

100's

Reverse

Configuration

1's

V+

POL

1's

10's

OSC1

TEST

REF

ANALOG

COMMON

OSC2

OSC3

REF

BUFF

INT

V-

BP/GND

(7106A/7107A)

TEST

OSC3

OSC2

OSC1

V+

REF HI

TC7106ACKW

TC7107ACKW

REF LO

REF

COM

IN HI

IN LO

A/Z

BUFF

INT

V-

BP/GND

POL

REF LO

REF

TC7106ACLW

TC7107ACLW

V+

OSC1

OSC2

OSC3

TEST

REF HI

POL

BP/GND

REF

COMMON

IN HI

IN LO

A/Z

BUFF

INT

V-

TC7106/A/TC7107/A

DS21455B-page 4

2002 Microchip Technology Inc.

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

≤

70°C) (Note 2):

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

Storage Temperature Range .............. -65°C to +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

≤

70°C) (Note 2):

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

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

*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.

TC7106/A AND TC7107/A ELECTRICAL SPECIFICATIONS

Electrical Characteristics: Unless otherwise noted, specifications apply to both the TC7106/A and TC7107/A at T

= 25°C,

CLOCK

= 48kHz. Parts are tested in the circuit of the Typical Operating Circuit.

Symbol

Parameter

Min

Typ

Max

Unit

Test Conditions

Zero Input Reading

-000.0

±000.0

+000.0

Digital

Reading

= 0.0V

Full Scale = 200.0mV

Ratiometric Reading

999

999/1000

1000

Digital

Reading

= V

REF

= 100mV

R/O

Rollover Error (Difference in Reading for

Equal Positive and Negative

Reading Near Full Scale)

-1

±0.2

Counts

- = + V

≅

200mV

Linearity (Max. Deviation from Best

Straight Line Fit)

-1

±0.2

Counts

Full Scale = 200mV or

Full Scale = 2.000V

Note

Input voltages may exceed the supply voltages, provided the input current is limited to ±100

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

Refer to “Differential Input” discussion.

Backplane drive is in phase with segment drive for “OFF” segment, 180° out of phase for “ON” segment.

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

2002 Microchip Technology Inc.

DS21455B-page 5

TC7106/A/TC7107/A

CMRR

Common Mode Rejection Ratio (Note 3)

—

V/V

= ±1V, V

= 0V,

Full Scale = 200.0mV

Noise (Peak to Peak Value not Exceeded

95% of Time)

—

= 0V

Full Scale - 200.0mV

Leakage Current at Input

—

= 0V

Zero Reading Drift

—

0.2

V/°C

= 0V

“C” Device = 0°C to +70°C

—

1.0

V/°C

= 0V

“I” Device = -25°C to +85°C

Scale Factor Temperature Coefficient

—

ppm/°C

= 199.0mV,

“C” Device = 0°C to +70°C

(Ext. Ref = 0ppm°C)

—

ppm/°C

= 199.0mV

“I” Device = -25°C to +85°C

Supply Current (Does not include LED

Current For TC7107/A)

—

0.8

1.8

= 0.8

Analog Common Voltage

(with Respect to Positive Supply)

2.7

3.05

3.35

25k

Ω

Between Common and

Positive Supply

CTC

Temperature Coefficient of Analog

Common (with Respect to Positive Supply)

—

25k

Ω

Between Common and

Positive Supply

7106/7/A

7106/7

—

ppm/°C

0°C

≤

+70°C

(“C” Commercial Temperature

Range Devices)

CTC

Temperature Coefficient of Analog

Common (with Respect to Positive Supply)

—

ppm/°C

0°C

≤

+70°C

(“I” Industrial Temperature

Range Devices)

TC7106A ONLY Peak to Peak

Segment Drive Voltage

V+ to V- = 9V

(Note 4)

TC7106A ONLY Peak to Peak

Backplane Drive Voltage

V+ to V- = 9V

(Note 4)

TC7107A ONLY

Segment Sinking Current (Except Pin 19)

8.0

—

V+ = 5.0V

Segment Voltage = 3V

TC7107A ONLY

Segment Sinking Current (Pin 19)

—

V+ = 5.0V

Segment Voltage = 3V

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

Electrical Characteristics: Unless otherwise noted, specifications apply to both the TC7106/A and TC7107/A at T

= 25°C,

CLOCK

= 48kHz. Parts are tested in the circuit of the Typical Operating Circuit.

Symbol

Parameter

Min

Typ

Max

Unit

Test Conditions

Note

Input voltages may exceed the supply voltages, provided the input current is limited to ±100

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

Refer to “Differential Input” discussion.

Backplane drive is in phase with segment drive for “OFF” segment, 180° out of phase for “ON” segment.

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

TC7106/A/TC7107/A

DS21455B-page 6

2002 Microchip Technology Inc.

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

Pin No.

(40-Pin PDIP)

(Reversed

Symbol

Description

(40)

V+

Positive supply voltage.

(39)

Activates the D section of the units display.

(38)

Activates the C section of the units display.

(37)

Activates the B section of the units display.

(36)

Activates the A section of the units display.

(35)

Activates the F section of the units display.

(34)

Activates the G section of the units display.

(33)

Activates the E section of the units display.

(32)

Activates the D section of the tens display.

(31)

Activates the C section of the tens display.

(30)

Activates the B section of the tens display.

(29)

Activates the A section of the tens display.

(28)

Activates the F section of the tens display.

(27)

Activates the E section of the tens display.

(26)

Activates the D section of the hundreds display.

(25)

Activates the B section of the hundreds display.

(24)

Activates the F section of the hundreds display.

(23)

Activates the E section of the hundreds display.

(22)

Activates both halves of the 1 in the thousands display.

(21)

POL

Activates the negative polarity display.

(20)

BP/GND

LCD Backplane drive output (TC7106A). Digital Ground (TC7107A).

(19)

Activates the G section of the hundreds display.

(18)

Activates the A section of the hundreds display.

(17)

Activates the C section of the hundreds display.

(16)

Activates the G section of the tens display.

(15)

V-

Negative power supply voltage.

(14)

INT

Integrator output. Connection point for integration capacitor. See INTEGRATING

CAPACITOR section for more details.

(13)

BUFF

Integration resistor connection. Use a 47k

Ω

resistor for a 200mV full scale range and

a 47k

Ω

resistor for 2V full scale range.

(12)

The size of the auto-zero capacitor influences system noise. Use a 0.47

F capacitor

for 200mV full scale, and a 0.047

F capacitor for 2V full scale. See Section 7.1 on

Auto-Zero Capacitor for more details.

(11)

The analog LOW input is connected to this pin.

(10)

The analog HIGH input signal is connected to this pin.

(9)

ANALOG

COMMON

This pin is primarily used to set the Analog Common mode voltage for battery opera-

tion or in systems where the input signal is referenced to the power supply. It also

acts as a reference voltage source. See Section 8.3 on ANALOG COMMON for more