1 Features

• 20 to 1 Frequency Range With an External

Resistor

• Logic Compatible Output With 100-mA Current

Sinking Capability

• Bandwidth Adjustable From 0 to 14%

• High Rejection of Out of Band Signals and Noise

• Immunity to False Signals

• Highly Stable Center Frequency

• Center Frequency Adjustable from 0.01 Hz to

500 kHz

2 Applications

• Touch Tone Decoding

• Precision Oscillator

• Frequency Monitoring and Control

• Wide Band FSK Demodulation

• Ultrasonic Controls

• Carrier Current Remote Controls

• Communications Paging Decoders

3 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.