2006 Microchip Technology Inc.
DS21459D-page 5
TC7129
2.0
PIN DESCRIPTIONS
TABLE 2-1:
PIN FUNCTION TABLE
Pin No.
40-Pin PDIP
Pin No.
44-Pin PQFP
Pin No.
44-Pin PLCC
Symbol
Function
1
40
2
OSC1
Input to first clock inverter.
2
41
3
OSC3
Output of second clock inverter.
3
42
4
ANNUNCIATOR
Backplane square wave output for driving annunciators.
443
5
B1, C1, CONT
Output to display segments.
544
6
A1, G1, D1
Output to display segments.
61
7
F1, E1, DP1
Output to display segments.
72
8
B2, C2,
LO BATT
Output to display segments.
83
9
A2, G2, D2
Output to display segments.
94
10
F2, E2, DP2
Output to display segments.
10
5
11
B3, C3, MINUS
Output to display segments.
11
7
13
A3, G3, D3
Output to display segments.
12
8
14
F3, E3, DP3
Output to display segments.
13
9
15
B4, C4, BC5
Output to display segments.
14
10
16
A4, D4, G4
Output to display segments.
15
11
17
F4, E4, DP4
Output to display segments.
16
12
18
BP3
Backplane #3 output to display.
17
13
19
BP2
Backplane #2 output to display.
18
14
20
BP1
Backplane #1 output to display.
19
15
21
VDISP
Negative rail for display drivers.
20
16
22
DP4/OR
Input: When high, turns on most significant decimal point.
Output: Pulled high when result count exceeds ±19,999.
21
18
24
DP3/UR
Input: Second-most significant decimal point on when high.
Output: Pulled high when result count is less than ±1000.
22
19
25
LATCH/HOLD
Input: When floating, ADC operates in Free Run mode. When
pulled high, the last displayed reading is held. When pulled low,
the result counter contents are shown incrementing during the
de-integrate phase of cycle.
Output: Negative going edge occurs when the data latches are
updated. Can be used for converter status signal.
23
20
26
V–
Negative power supply terminal.
24
21
27
V+
Positive power supply terminal and positive rail for display
drivers.
25
22
28
INT IN
Input to integrator amplifier.
26
23
29
INT OUT
Output of integrator amplifier.
27
24
30
CONTINUITY
Input: When low, continuity flag on the display is off. When high,
continuity flag is on.
Output: High when voltage between inputs is less than +200 mV.
Low when voltage between inputs is more than +200 mV.
28
25
31
COMMON
Sets common mode voltage of 3.2V below V+ for DE, 10X, etc.
Can be used as pre-regulator for external reference.
29
26
32
CREF+
Positive side of external reference capacitor.
30
27
33
CREF–
Negative side of external reference capacitor.
31
29
35
BUFFER
Output of buffer amplifier.
32
30
36
IN LO
Negative input voltage terminal.
33
31
37
IN HI
Positive input voltage terminal.
34
32
38
REF HI
Positive reference voltage.
35
33
39
REF LO
Negative reference voltage