Audio ICs Headphone driver for digital audio BA3578FS / BA3579FS The BA3578FS and BA3579FS are headphone drivers with internal an LPF and fixed bass boost circuit for multi-bit D / A converters. Applications Portable CD players Features 1) Suitable for use in digital audio equipment (line-out output noise voltage: 18µVrms, S / N = 95dB Typ.). 2) Internal LPF for multi-bit D / A converters (fc = 34kHz, 12dB / oct. Typ.). 3) Headphone mute function. Absolute maximum ratings (Ta = 25C) Recommended operating conditions Recommended operating range 450 4) 5) 6) 7) Internal BB (bass boost) circuit. Internal supply current for line-mute transistor. No need for output oscillation preventive measures. Internal standby switch. Audio ICs BA3578FS / BA3579FS Block diagram 451 Audio ICs 452 BA3578FS / BA3579FS Audio ICs BA3578FS / BA3579FS Electrical characteristics (Unless otherwise noted, Ta = 25C, PVCC = AVDD = 3.6V, f = 1kHz, PwSw = ON, MUTE = OFF, BB = OFF, Line RL1 = 47kΩ, headphone RL2 = 32Ω, filter = DIN AUDIO, line-out measurements are with VIN3 and 4 = 0V) 453 Audio ICs Measurement circuits 454 BA3578FS / BA3579FS Audio ICs BA3578FS / BA3579FS 455 Audio ICs Measurement conditions 456 BA3578FS / BA3579FS Audio ICs BA3578FS / BA3579FS Application examples 457 Audio ICs 458 BA3578FS / BA3579FS Audio ICs BA3578FS / BA3579FS Circuit operation (1) By operating the BA3578FS and BA3579FS according to the timing chart shown in Fig. 5, it is possible to suppress generation of “pop” noise in the headphone output. (2) The voltage of the BIAS pin (pin 11) for the BA3578FS and BA3579FS is the voltage divided from the AVDD pin (pin 1). There is no current carrying capacity, so do not use it as an operating point for external circuits. 459 Audio ICs BA3578FS / BA3579FS Electrical characteristic curves External dimensions (Unit: mm) 460