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.