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.