Overview
The LA1837M is a single-chip AM/FM tuner IC that provides AM and FM IF and multiplex decoding circuits for electronic tuning and was developed for use in home stereo systems. It provides both SD and IF counting techniques for optimal implementation of automatic station selection.

Features
• On-chip MPX VCO circuit (no external components required).
• Adjacent channel interference rejection function (third order and fifth order).
• Supports both the SD and IF counting technique (built-in SD speedup function).
• The AM and FM SD sensitivity can be set independently.
• The AM and FM output levels can be set independently.
• Improved basic FM reception performance.

Functions
• AM: RF amplifier, mixer, oscillator, IF amplifier, detector, AGC, oscillator buffer, S-meter, narrow band SD, IF buffer
• FM IF: IF amplifier, quadrature detector, S-meter, SD, S curve detection, IF buffer output
• Multiplex stereo decoding: PLL stereo decoder, stereo indicator, forced monaural, VCO stop function, post amplifier, audio muting, adjacent channel interference rejection function