The NTE1489 is a silicon monolithic integrated circuit in a 16Lead DIP type package designd for use as an FM multiplex demodulator for high class stere FM tuners. As the IC adopts a PLL (Phase Lock Loop) system, complexity of contol is usually experienced when using conventional external coil is eliminated and the demodulator can easily be constructed by simply controlling the external semi fixed potentiometer. Internal circuits are composed of a stereo demodulator, a lamp driver, an input stage preamplifier that is capable of establishing variable input signal levels, a VCO (Voltage Controlled Oscillator) constituting PLL, a phase comparator, a LPF (Low Pass Filter), a frequency divider, and a DC amplifier. A stereomonaural automatic switching circuit, a circuit for manual switching, VCO forced stop circuit, etc. are builtin. Features: