ICL7126_14 Datasheet, PDF (11/15 Pages) Intersil Corporation – 3 1/2 Digit, Low Power, Single Chip A/D Converter

ICL7126
Typical Applications
OSC 1 40
OSC 2 39
180kΩ
OSC 3 38
TEST 37
50pF
SET V_REF
= 100mV
REF HI 36
V+ 35
C_REF 34
C_REF 33
COMMON 32
IN HI 31
IN LO 30
A-Z 29
BUFF 28
0.1µF
10kΩ 220kΩ
0.33µF
180kΩ
1MΩ
0.01µF
INT 27
V - 26 ^750kΩ
0.047µF
G2 25
C3 24
A3 23
TO DISPLAY
G3 22
BP/GND 21
TO BACKPLANE
+
IN
-
9V
Values shown are for 200mV full scale, 3 readings/sec., floating
supply voltage (9V battery).
FIGURE 10. ICL7126 USING THE INTERNAL REFERENCE
OSC 1 40
OSC 2 39
OSC 3 38
TEST 37
REF HI 36
V+ 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/GND 21
560kΩ
50pF
20kΩ
SET V_REF
= 100mV
0.1µF
V+
200kΩ 27kΩ
0.33µF
180kΩ
1MΩ
0.01µF
+
IN
-
0.15µF
V-
TO DISPLAY
IN LO is tied to COMMON, thus establishing the correct common
mode voltage. COMMON acts as a pre-regulator for the reference.
Values shown are for 1 reading/sec.
FIGURE 11. ICL7126 WITH AN EXTERNAL BAND-GAP
REFERENCE (1.2V TYPE)
OSC 1 40
OSC 2 39
OSC 3 38
TEST 37
REF HI 36
V+ 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/GND 21
180kΩ
50pF
SET V_REF
= 1.000V
0.1µF
250kΩ 240kΩ
0.22µF
1.8MΩ
1MΩ
0.01µF
750Ω 0.047µF
TO DISPLAY
TO BACK PLANE
V+
+
IN
-
V^-
3 reading/s. For 1 reading/sec., delete 750Ω resistor, change C_INT,
R_OSC to values of Figure 11.
FIGURE 12. RECOMMENDED COMPONENT VALUES FOR 2.0V
FULL SCALE
OSC 1 40
OSC 2 39
OSC 3 38
TEST 37
REF HI 36
V+ 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/GND 21
100kΩ
100pF
SET V_REF
= 100mV
0.1µF
+5V
1kΩ 10kΩ 15kΩ
1.2V (ICL8069)
1MΩ
+
0.01µF
IN
0.47µF
-
47kΩ
0.22µF
TO DISPLAY
Since low TC zeners have breakdown voltages ~6.8V, diode must be
placed across the total supply (10V). As in the case of Figure 12, IN
LO may be tied to COMMON.
FIGURE 13. ICL7126 WITH ZENER DIODE REFERENCE
11
FN3084.5