This circuit requires low noise, low and stable offset voltages, high open loop gain, and high speed. These requirements are met by the HA514 7. The standard variations of this circuit can easily be implemented using the HA-5147. For example, hysteresis can be generated by adding R1 to provide small amounts of positive feedback.
The circuit becomes a pulse width modulator if V,,r and the input signal are left to vary. Although the output drive capability of this device is excellent, the optional buffering circuit can be used to drive heavier loads, preventing loading effects on the amplifier.