TC820 TelCom Semiconductor, TC820 Datasheet - Page 5

• Manufacturer Part Number: TC820
• Description: 3-3/4 DIGIT A/D CONVERTER WITH FREQUENCY COUNTER AND LOGIC PROBE
• Manufacturer: TelCom Semiconductor

PIN DESCRIPTION
3-3/4 A/D CONVERTER WITH
FREQUENCY COUNTER
AND LOGIC PROBE
Package)
Pin No.
(40-Pin
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
TELCOM SEMICONDUCTOR, INC.
(44-Pin Flat
Package)
Pin No.
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
BUZOUT
PKHOLD
Symbol
DP0/LO
DP1/HI
VOLTS
FREQ/
BUZIN
HOLD
V
OSC1
OSC2
OSC3
EOC/
COM
C
C
V
V
V
V
C
UR
OR
V
V
V
BUFF
REF
REF
+
REF
–
REF
+
–
INT
SS
AZ
–
IN
+
IN
DD
Description
Dual-purpose input. Decimal point select input for voltage measurements. In logic
mode, connecting this pin to V
internal 5 A pull-down to DGND in volts mode only. Decimal point logic:
Dual-purpose input. Decimal point select input for voltage measurements. In logic
mode, connecting this pin to V
internal 5 A pull-down to DGND in volts mode only.
Buzzer output. Audio frequency, 5kHz, output which drives a piezoelectric buzzer.
Buzzer control input. Connecting BUZIN to V
logically ORed (internally) with the "logic level low" input. There is an internal 5 A
pull-down to DGND.
Voltage or frequency measurement select input. When unconnected, or connected
to DGND, the A/D converter function is active. When connected to V
frequency counter function is active. This pin has an internal 5 A pull-down
to DGND.
Peak hold input. When connected to V
if a new conversion value is greater than the preceding value. Thus, the peak
reading will be stored and held indefinitely. When unconnected, or connected to
DGND, the converter will operate normally. This pin has an internal 5 A pull-down
to DGND.
Underrange output. This output will be HIGH when the digital reading is 380 counts
or less.
Overrange output. This output will be HIGH when the analog signal input is greater
than full scale. The LCD will display "OL" when the input is overranged.
Negative supply connection. Connect to negative terminal of 9V battery.
Analog circuit ground reference point. Nominally 3.3V below V
Positive connection for reference capacitor.
Negative connection for reference capacitor.
High differential reference input connection.
Low differential reference input connection.
Low analog input signal connection.
High analog input signal connection.
Buffer output. Connect to integration resistor.
Auto-zero capacitor connection.
Integrator output. Connect to integration capacitor.
Bidirectional pin. Pulses low (i.e., from V
conversion. If connected to V
updated.
Crystal oscillator (input) connection.
Crystal oscillator (output) connection.
RC oscillator connection.
Positive power supply connection, typically 9V.
DP1
0
0
1
1
DP0
0
1
0
1
Decimal Point Selected
DD
DD
DD
, conversions will continue, but the display is not
None
DP1
DP2
DP3
will turn on the "low" LCD segment. There is an
will turn on the "high" LCD segment. There is an
DD
DD
, the converter will only update the display
to DGND) at the end of each
DD
turns the buzzer on. BUZIN is
DD
.
DD
, the
TC820
3-153
1
2
3
4
5
6
7
8