Lm3189 Fm If System - National Semiconductor

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 desir- able 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 log- ic. In addition, internal power supply Regulators maintain a nearly constant current drain over the voltage supply range of a8.5V to a16V. 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. By National Semiconductor Corporation