
4
TC8129
4C\VDigit Auto-Ranging DMM ADC
TC8129 - 3/29/96-2
2001 Microchip Technology Inc.
DS21473A
PIN DESCRIPTION
Pin No.
(44-Pin flat
Package)
Symbol
Description
1
DGND1
Internal logic digital ground. Nominally 5V below V
+
S.
2
DNGD2
Power supply ground connection for the TC8131 controller. Nominally 3V below V
+
S.
3V
+
S
Positive power supply connection, typically 9V.
4V
–
S
Negative supply connection. Connect to negative terminal of 9V battery
5
101k
Connection for 101k
range resistor.
6
1.1MEG
Connection for 1.1M
range resistor.
7
10MEG
Connection for 10M
range resistor.
8
mV/RREF
Dual purpose input. In voltage mode, this pin provides an input which bypasses the
10M
input resistor to minimize the effect of leakages. In the resistance mode, this pin
measures the voltage across the reference resistor.
9
IRC
In current, resistance and capacitance modes, this pin senses the voltage across the
current sense resistor, unknown resistor, and capacitor, respectively.
10
10k
Connection for 10k
range resistor.
11
1k
Connection for 1k
range resistor.
12
VLCTRM
Voltage reference input for lower range capacitance measurement. See Text.
13
VHCTRM
Voltage reference input for upper range capacitance measurement. See Text.
14
VREFR
Voltage reference input for resistance measurements. Typically 1.2V.
15
CAP
+
Current source output for capacitance measurements.
16
COM
Analog circuit ground reference point. Nominally 3.2V below V
+
S.
17
ADO
Output of AC to DC converter Op Amp.
18
ADI
Inverting input of AC to DC converter Op Amp.
19
ACVL
Ground input for AC to DC converter.
20
ACVH
DC result of AC to DC conversion.
21
V
–
IN
Low analog input signal connection.
22
INTIN
Inverting input of the integrator Op Amp.
23
INTOUT
Output of the integrator. Connect to integration capacitor.
24
C
+
REF
Positive connection for reference capacitor.
25
C
–
REF
Negative connection for reference capacitor.
26
V
+
REF
High differential reference input connection.
27
V
–
REF
Low differential reference input connection
28
BUF
Buffer output.
29
NC
No connection.
30
CONT
Output of the fast continuity comparator.
31
BUZIN
Control input for the on-chip buzzer driver.
32
BUZOUT
Buzzer output. Audio frequency output at 2048Hz, which drives a piezo buzzer.
33
NC
No connection.
34
fIN
Frequency prescaler input.
35
DV
Data Valid output. This pin goes LOW at the end of a conversion. It will stay LOW until
data is read out of the TC8129.
36
fOUT
Output of frequency prescaler. Used by controller to extend range of the frequency
counter beyond 4kHz.
37
DATA
Bidirectional data input/output.
38
RD
Data Read input. When RD is LOW, data can be read from the TC8129.
39
NC
No connection.