ca3160t Intersil Corporation, ca3160t Datasheet - Page 13

• Manufacturer Part Number: ca3160t
• Description: 4mhz, Bimos Operational Amplifier With Mosfet Input/cmos Output
• Manufacturer: Intersil Corporation

input current to the less than one picoampere level can be
achieved as shown in Figure 23.
To further enhance the stability of this circuit, the CA3160
can be operated with its output (Terminal 6) near ground,
thus markedly reducing the dissipation by reducing the
supply current to the device.
The CA3140 stage serves as a X100 gain stage to provide
the required plus and minus output swing for the meter and
feedback network. A 100-to-1 voltage divider network
consisting of a 9.9k resistor in series with a 100 resistor
sets the voltage at the 10G resistor (in series with Terminal
3) to 30mV full-scale deflection. This 30mV signal results
from 3V appearing at the top of the voltage divider network
which also drives the meter circuitry.
By utilizing a switching technique in the meter circuit and in
the 9.9k and 100 network similar to that used in voltmeter
circuit shown in Figure 8, a current range of 3pA to 1nA full
scale can be handled with the single 10G resistor.
FIGURE 11. CURRENT-TO-VOLTAGE CONVERTER TO PROVIDE A PICOAMMETER WITH 3pA FULL SCALE DEFLECTION
1M
VOLTAGE
ADJUST
OFFSET
10M
30pF
3
2
100k
2k
FIGURE 12A. SINGLE SUPPLY SAMPLE AND HOLD SYSTEM, INPUT 0V TO 10V
+15V
1
13
CA3160
+
-
9.1k
7
5
3
2
100k
4
100k
CA3160
+
-
1
9.1k
8
+15V
0.1 F
7
5
8.2k
6
4
0.1 F
6
560k
CA3160, CA3160A
10k
-15V
SAMPLE =
0.1 F
1N914
10G
10pF
HOLD =
STROBE INPUT
2
3
500 A
27k
CA3080A
15V
-
+
5
0V
2
3
0.1 F
7
4
COMPARATOR
1M
ADJUST
OSCILLATOR
-15V
DROOP
+15V
CA3140
STAIRCASE
+
-
ZERO
100k
2V STEPS
FIGURE 10B. STAIRCASE GENERATOR WAVEFORM
6
0.1 F
OUTPUT
7
4
FIGURE 10. STAIRCASE GENERATOR CIRCUIT
+15V
39k
39k
Top Trace: Staircase Output 2V Steps
6
9.9k
1M
100
Center Trace: Comparator
Bottom Trace: Oscillator
8.2
0.1 F
2200pF
2
3
M
CA3140
+
-
5.6k
500
500-0-500 A
+15V
7
4
0.1 F
6