Optical disc ICs 4-channel BTL driver for CD players BA6790FP / BA6791FP The BA6790FP and BA6791FP are 4-channel BTL drivers for CD player actuators and motors. These ICs have internal 5 V regulators and general purpose operational amplifiers, and are mounted to a 28-pin HSOP package, allowing for the miniaturization of applications. Applications CD players and portable CD Features 1) 4-channel BTL driver. 2) HSOP 28-pin package allows for miniaturization of applications. 3) Wide dynamic range. (typically 5.4V when VCC = 8V and RL = 8Ω) Block diagram 348 4) Internal thermal shutdown circuit. 5) Gain is adjustable with a single attached resistor. 6) Internal 5V regulator. (requires attached PNP transistor) 7) Internal general purpose operational amplifier. Optical disc ICs BA6790FP/BA6791FP FPin descriptions FAbsolute maximum ratings (Ta = 25_C) FRecommended operating conditions 349 Optical disc ICs BA6790FP/BA6791FP FElectrical characteristics (unless otherwise noted, Ta = 25_C, VCC = 8V, f = 1kHz, RL = 8Ω) 350 Optical disc ICs BA6790FP/BA6791FP Measurement circuit 351 Optical disc ICs Measurement circuit switch table Input / output circuits 352 BA6790FP/BA6791FP Optical disc ICs BA6790FP/BA6791FP Application example 353 Optical disc ICs FThermal derating curve FExternal dimensions (Units: mm) 354 BA6790FP/BA6791FP FOperation notes (1) The BA6790FP and BA6791FP have an internal thermal shutdown circuit. Output current is muted when the chip temperature exceeds 175_C (typically) and restored when the chip temperature falls to 150_C (typically). (2) If the mute pin (pin 7) voltage is opened or lowered below 0.5V, the output current will be muted. Pin 7 should be pulled up above 2.0V during normal use. (3) The bias pin (pin 23) is muted when lowered below 1.4V (typically). Make sure it stays above 1.6V during normal use. (4) Muting occurs during thermal shutdown, mute-on operations or a drop in the bias pin voltage. In each case, only the drivers are muted. During muting, the output pins remain at the internal bias voltage, roughly (VCC / 2). (5) Be sure to connect the IC to a 0.1µF bypass capacitor to the power supply, at the base of the IC. (6) The radiating fin is connected to the packages internal GND, but should also be connected to an external ground. (7) The capacitor between regulator output (pin 6) and GND also serves to prevent oscillation of the IC, so select one with good temperature characteristics.