LM1863

www.DataSheet4U.com LM1863 AM Radio System for Electronically Tuned Radios May 1989 LM1863 AM Radio System for Electronically Tuned Radios General Description The LM1863 is a high performance AM radio system intended primarily for electronically tuned radios Important to this application is an on-chip stop detector circuit which allows for a user adjustable signal level threshold and center frequency stop window The IC uses a low phase noise levelcontrolled local oscillator Low phase noise is important for AM stereo which detects phase noise as noise in the L-R channel A buffered output for the local oscillator allows the IC to directly drive a phase locked loop synthesizer The IC uses a RF AGC detector to gain reduce an external RF stage thereby preventing overload by strong signals An improved noise floor and lower THD are achieved through gain reduction of the IF stage Fast AGC settling time which is important for accurate stop detection and excellent THD performance are achieved with the use of a two pole AGC system Low tweet radiation and sufficient gain are provided to allow the IC to also be used in conjunction with a loopstick antenna Features Y Y Y Y Y Y Y Y Y Y Low supply current Level-controlled low phase noise local oscillator Buffered local oscillator output Stop circuitry with adjustable stop threshold and adjustable stop window Open collector stop output Excellent THD and stop time performance Large amount of recovered audio RF AGC with open collector out...