General Description
The LM567 and LM567C are general purpose tone decoders
designed to provide a saturated transistor switch to ground
when an input signal is present within the passband. The
circuit consists of an I and Q detector driven by a voltage
controlled oscillator which determines the center frequency
of the decoder. External components are used to independently
set center frequency, bandwidth and output delay.

Features
n 20 to 1 frequency range with an external resistor
n Logic compatible output with 100 mA current sinking
capability
n Bandwidth adjustable from 0 to 14%
n High rejection of out of band signals and noise
n Immunity to false signals
n Highly stable center frequency
n Center frequency adjustable from 0.01 Hz to 500 kHz