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
V
30
C
29
28
V
27
V
26
V-
25
G
24
C
23
A
22
G
21
BP/GND
(7106A/7107A)
REF
REF
REF
REF
IN
IN
AZ
BUFF
INT
2
3
3
3
+
-
+
-
+
-
100's
OSC1
OSC2
OSC3
TEST
V
REF
V
REF
C
REF
C
REF
ANALOG
COMMON
V
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)
(Note 4)
Segment Voltage = 3V
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.
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