Audio ICs AM radio / FM IF stereo system IC BA1448S / BA1449F The BA1448S and BA1449F are electronic tuning system ICs for AM, FM IF, and MPX. They have been developed for use in radio cassette players and mini-component stereo systems. The FM detector and MPX VCO circuits do not require adjustment, which will reduce the number of assembly line processes. In particular, the VCO is laser locked, and requires no adjustment or external components. The characteristics of the two chips are the same, but the packages are different (24-pin SDIP for the BA1448S and 24-pin SOP for the BA1449F). Applications Synthesized tuners in radio cassette players and minicomponent stereo systems. Features 1) Built-in mono AM radio, FM IF amplifier / detector, and FM stereo demodulator. 2) DTS compatible (both SD and IF count). 3) Built-in reference voltage supply for good short-wave band frequency stability. 4) Good FM stability. 5) FM detector does not require adjustment (ceramic discriminator). Absolute maximum ratings (Ta = 25C) Recommended operating conditions (Ta = 25C) 354 6) FM MPX VCO is laser locked and requires no adjustment or external components. 7) Built-in forced monaural function for the MPX (VCO stops, LED off). 8) Audio can be low-cut to improve AM fidelity. 9) VCO for the MPX switches off during AM operation. 10) Mute possible for IF request. Audio ICs BA1448S / BA1449F Block diagram 355 Audio ICs Input / output circuits 356 BA1448S / BA1449F Audio ICs BA1448S / BA1449F 357 Audio ICs 358 BA1448S / BA1449F Audio ICs BA1448S / BA1449F Electrical characteristics (unless otherwise noted, Ta = 25C, VCC = 5V) Signal source FM IF MPX: fIN = 10.7MHz, 1kHz modulation 22.5kHz dev (30%), Signal source FM IF MPX fIN = 10.7MHz, 19kHz modulation 7.5kHz dev (10%) Signal source AM IF MPX: fIN = 1000kHz, 1kHz modulation 30% 359 Audio ICs Measurement circuit 360 BA1448S / BA1449F Audio ICs BA1448S / BA1449F Application example Electrical characteristic curves 361 Audio ICs External dimensions (Units: mm) 362 BA1448S / BA1449F