1 Features

1• Functionally Similar to LM567

• 2-V to 9-V Supply Voltage Range

• Low Supply Current Drain

• No Increase in Current With Output Activated

• Operates to 500-kHz Input Frequency

• High Oscillator Stability

• Ground-Referenced Input

• Hysteresis Added to Amplitude Comparator

• Out-of-Band Signals and Noise Rejected

• 20-mA Output Current Capability

2 Applications

• Touch-Tone Decoding

• Precision Oscillators

• Frequency Monitoring and Control

• Wide-Band FSK Demodulation

• Ultrasonic Controls

• Carrier Current Remote Controls

• Communications Paging Decoders

3 Description

The LMC567 device is a low-power, general-purpose

LMCMOS tone decoder which is functionally similar to the industry standard LM567. The device consists

of a twice frequency voltage-controlled oscillator

(VCO) and quadrature dividers which establish the

reference signals for phase and amplitude detectors.

The phase detector and VCO form a phase-locked

loop (PLL) which locks to an input signal frequency which is within the control range of the VCO. When

the PLL is locked and the input signal amplitude

exceeds an internally pre-set threshold, a switch to

ground is activated on the output pin. External

components set up the oscillator to run at twice the

input frequency and determine the phase and amplitude filter time constants.