ca3160t Intersil Corporation, ca3160t Datasheet - Page 14

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

SAMPLING
Single Supply Sample-and-Hold System
Figure 12 shows a single supply sample-and-hold system
using a CA3160 to provide a high input impedance and an
input voltage range of 0V to 10V. The output from the input
buffer integrator network is coupled to a CA3080A. The
CA3080A functions as a strobeable current source for the
CA3140 output integrator and storage capacitor. The
CA3140 was chosen because of its low output impedance
and constant gain-bandwidth product. Pulse “droop” during
the hold interval can be reduced to zero by adjusting the
100k bias-voltage potentiometer on the positive input of
the CA3140. This zero adjustment sets the CA3080A output
voltage at its zero current position. In this sample-and-hold
circuit it is essential that the amplifier bias current be
reduced to zero to minimize output signal current during the
hold mode. Even with 320mV at the amplifier bias circuit
terminal (5) at least 1100pA of output current will be
available.
Wien Bridge Oscillator
A simple, single supply Wien Bridge oscillator using a
CA3160 is shown in Figure 13. A pair of parallel-connected
1N914 diodes comprise the gain-setting network which
standardizes the output voltage at approximately 1.1V. The
500
always start and the oscillation will be maintained.
Increasing the amplitude of the voltage may lower the
threshold level for starting and for sustaining the oscillation,
but will introduce more distortion.
SAMPLED
OUTPUT
PULSES
SIGNAL
INPUT
potentiometer is adjusted so that the oscillator will
FIGURE 12B. SAMPLE AND HOLD WAVEFORM
Bottom Trace: Sampling Pulses
Top Trace: Sampled Output
Center Trace: Input Signal
FIGURE 12. SINGLE SUPPLY SAMPLE AND HOLD SYSTEM, INPUT 0V TO 10V
14
CA3160, CA3160A
SAMPLING
Operation with Output Stage Power Booster
The current sourcing and sinking capability of the CA3160
output stage is easily supplemented to provide power-boost
capability. In the circuit of Figure 14, three CMOS transistor-
pairs in a single CA3600 lC array are shown parallel-connected
with the output stage in the CA3160. In the Class A mode of
CA3600E shown, a typical device consumes 20mA of supply
current at 15V operation. This arrangement boosts the current-
handling capability of the CA3160 output stage by about 2.5X.
The amplifier circuit in Figure 14 employs feedback to
establish a closed-loop gain of 20dB. The typical large-
signal-bandwidth (-3dB) is 190kHz.
SAMPLED
INPUT 0V-
100k
100k
OUTPUT
PULSES
FIGURE 13. SINGLE SUPPLY WEIN BRIDGE OSCILLATOR
f =
R
R
2
1
0V-
2
FIGURE 12C. SAMPLE AND HOLD WAVEFORM
C
10-80
pF
51pF
1
(R
C
2
1
|| R
1
Bottom Trace: Sampling Pulses
2
) C
Top Trace: Sampled Output
51k
Center Trace: Input Signal
R
1
3
3
2
R
3
C
+
CA3160
2
-
7
4
+15V
0.1
F
2k
6
0.01 F
680
OUTPUT
f = 100kHz
2% THD AT 1.1V
500
2-1N914
P-P