LMC567 Low Power Tone Decoder
June 1999
LMC567 Low Power Tone Decoder
General Description
The LMC567 is a low power general purpose LM
CMOS™ tone decoder which is functionally similar to the industry standard LM567.
It 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...