HCA10014 Datasheet, PDF (15/17 Pages) Intersil Corporation – 15MHz, BiMOS Operational Amplifier with MOSFET Input/CMOS Output

HCA10014
The heart of the frequency determining system is an
operational transconductance amplifier (OTA) (see Note 9),
lC₁, operated as a voltage controlled current source. The
output, I_O, is a current applied directly to the integrating
capacitor, C₁, in the feedback loop of the integrator lC₂,
using a HCA10014, to provide the triangular wave output.
Potentiometer R₂ is used to adjust the circuit for slope
symmetry of positive going and negative going signal
excursions.
Another HCA10014, IC₃, is used as a controlled switch to
set the excursion limits of the triangular output from the
integrator circuit. Capacitor C₂ is a “peaking adjustment” to
optimize the high frequency square wave performance of the
circuit.
Potentiometer R₃ is adjustable to perfect the “amplitude
symmetry” of the square wave output signals. Output from
the threshold detector is fed back via resistor R₄ to the input
of lC₁ so as to toggle the current source from plus to minus
in generating the linear triangular wave.
Operation with Output Stage Power Booster
The current sourcing and sinking capability of the
HCA10014 output stage is easily supplemented to provide
power boost capability. In the circuit of Figure 23, three
CMOS transistor pairs in a single CA3600E (see Note 11) lC
array are shown parallel connected with the output stage in
the HCA10014. 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 output stage by about 2.5X.
The amplifier circuit in Figure 23 employs feedback to
establish a closed loop gain of 48dB. The typical large signal
bandwidth (-3dB) is 50kHz.
NOTE:
8. See Document # 619 (CA3600E) for technical information.
R₁
100kΩ
R₂
100kΩ
+15V
ON-PERIOD
ADJUST
1MΩ
OFF-PERIOD
ADJUST
1MΩ
0.01µF
2kΩ
2kΩ
R₃
100kΩ
7
3
+
1µF
0.1µF
HCA10014
6
S₁
2
-
OUTPUT
4 _2kΩ
0.01µF ^0.001µF
Frequency Range:
Position of S₁
0.001µF
0.01µF
0.1µF
1µF
Pulse Period
4µs to 1ms
40µs to 10ms
0.4ms to 100ms
4ms to 1s
FIGURE 21. PULSE GENERATOR (ASTABLE
MULTIVIBRATOR) WITH PROVISIONS FOR
INDEPENDENT CONTROL OF “ON” AND “OFF”
PERIODS
15