Monolithic frequency-to-voltage converter with a high gain op amp. It operates a relay, lamp, or other load when the input frequency reaches or exceeds a selected rate.

The tachometer uses a charge pump technique and offers frequency doubling for low ripple, and full-input protection, and its output swings to the ground for a zero-frequency input.

The op-amp is fully compatible with the tachometer and has a floating transistor as its output. This feature allows either a ground or supply a referred load of up to 50 mA. The collector may be taken above VCC up to a maximum VCE of 28 V.

The two basic configurations offered include an 8-pin device with a ground-referenced tachometer input and an internal connection between the tachometer output and the op amp noninverting input. This version is well suited for single-speed or frequency switching or fully buffered frequency-to-voltage conversion applications.