ICL7136_14 Datasheet, PDF (12/15 Pages) Intersil Corporation – 31/2 Digit LCD, Low Power Display, A/D Converter with Overrange Recovery

ICL7136
OSC 1 40
OSC 2 39
TO PIN 1
†
OSC 3 38
TEST 37
REF HI 36
50pF
SCALE
FACTOR
ADJUST
REF LO 35
C_REF
34
0.1µF
C_REF 33
COMMON 32
100kΩ 1MΩ
200kΩ 470kΩ
22kΩ
IN HI 31
IN LO 30
A-Z 29
BUFF 28
INT 27
V - 26
0.01µF
0.47µF
†
ZERO
ADJUST
390kΩ
SILICON NPN
MPS 3704 OR
SIMILAR
+
9V
-
G2 25
C3 24
A3 23
TO DISPLAY
G3 22
BP 21
TO BACKPLANE
A silicon diode-connected transistor has a temperature coefficient
of about -2mV/^oC. Calibration is achieved by placing the sensing
transistor in ice water and adjusting the zeroing potentiometer for a
000.0 reading. The sensor should then be placed in boiling water
and the scale-factor potentiometer adjusted for a 100.0 reading.
† Value depends on clock frequency.
FIGURE 10. ICL7136 USED AS A DIGITAL CENTIGRADE
THERMOMETER
O /RANGE
U /RANGE
V+
TO LOGIC
V_CC
1 V+
2 D1
3 C1
4 B1
5 A1
6 F1
7 G1
8 E1
9 D2
10 C2
11 B2
12 A2
13 F2
14 E2
15 D3
16 B3
17 F3
18 E3
19 AB4
20 POL
OSC 1 40
OSC 2 39
OSC 3 38
TEST 37
REF HI 36
REF LO 35 _TO
C_REF
34
LOGIC
GND
C_REF 33
COMMON 32
IN HI 31
IN LO 30
A-Z 29
BUFF 28
INT 27
V- 26 V-
G2 25
C3 24
A3 23
G3 22
BP 21
CD4023 OR
74C10
CD4077
FIGURE 11. CIRCUIT FOR DEVELOPING UNDERRANGE AND
OVERRANGE SIGNAL FROM ICL7136 OUTPUTS
OSC 1 40
OSC 2 39
OSC 3 38
TEST 37
REF HI 36
REF LO 35
C_REF 34
C_REF 33
COMMON 32
IN HI 31
IN LO 30
A-Z 29
BUFF 28
INT 27
V - 26
G2 25
C3 24
A3 23
G3 22
BP 21
TO PIN 1
180kΩ
50pF
10µF
0.1µF
20kΩ
220kΩ
SCALE FACTOR ADJUST
(V_REF = 100mV FOR AC TO RMS)
470kΩ
1N914
CA3140
5µF
+
-
100kΩ
2.2MΩ
0.47µF
180kΩ
0.047µF
10µF
1µF
10kΩ
4.3kΩ
1µF 10kΩ 1µF
+
9V
100pF
-
(FOR OPTIMUM
BANDWIDTH)
0.22µF
TO DISPLAY
TO BACKPLANE
Test is used as a common-mode reference level to ensure compatibility with most op amps.
AC IN
FIGURE 12. AC TO DC CONVERTER WITH ICL7136
12
FN3086.6
July 21, 2005