LM3189

LM3189 FM IF System April 1987 LM3189 FM IF System General Description The LM3189N is a monolithic integrated circuit that provides all the functions of a comprehensive FM IF system The block diagram of the LM3189N includes a three stage FM IF amplifier limiter configuration with level detectors for each stage a doubly balanced quadrature FM detector and an audio amplifier that features the optional use of a muting (squelch) circuit The advanced circuit design of the IF system includes desirable deluxe features such as programmable delayed AGC for the RF tuner an AFC drive circuit and an output signal to drive a tuning meter and or provide stereo switching logic In addition internal power supply regulators maintain a nearly constant current drain over the voltage supply range of a 8 5V to a 16V The LM3189N is ideal for high fidelity operation Distortion in an LM3189N FM IF system is primarily a function of the phase linearity characteristic of the outboard detector coil The LM3189N has all the features of the LM3089N plus additions The LM3189N utilizes the 16-lead dual-in-line plastic package and can operate over the ambient temperature range of b 40 C to a 85 C Features Y Y Y Y Y Y Y Y Y Y Y Y Exceptional limiting sensitivity 12 mV typ at b3 dB point Low distortion 0 1% typ (with double-tuned coil) Single-coil tuning capability Improved (S a N) N ratio Externally programmable recovered audio level Provides specific signal for control of inter-channel muting (squelch) P...