Optical disc ICs BTL driver for CD-ROMs BA5972FP The BA5972FP is a 4-channel BTL driver developed for use with CD-ROMs. A multi-purpose operational amplifier is equipped in each channel to allow use in a variety of applications. Also, by applying independent power supplies for both the pre-stage and power-stage, with the power-stage power supply further split into two so one power supply handles two channels each, a highly efficient driver has been realized. FApplications CD-ROM, DVD-ROM, MD, and optical discs FFeatures 1) Wide dynamic range (VOUT = 4V [Typ.] when PreVCC = 8V, PowVCC = 5V, and RL = 8Ω). 2) Internal thermal shutdown circuit. FAbsolute maximum ratings (Ta = 25_C) FRecommended operating conditions (Ta = 25_C) 662 3) Internal mute functions. 4) Internal standby functions. Optical disc ICs BA5972FP Block diagram Pin descriptions 663 Optical disc ICs Input / output circuits 664 BA5972FP Optical disc ICs BA5972FP FElectrical characteristics (unless otherwise noted, Ta = 25_C, PreVCC = 8V, PowVCC1 = 5V, PowVCC2 = 8V, BIAS = 2.5V, FElectrical characteristics (RL = 8Ω) 665 Optical disc ICs Measurement circuit 666 BA5972FP Optical disc ICs BA5972FP Measurement circuit switch table (1) Circuit current and standby (VMT = 0V, VIN = 2.5V, RL ! OFF, OPB ! 1, NF ! 1, OPRL ! 1) (2) Driver block (VST = 5V, RL ! ON, OPB ! 1, NF ! 1, OPRL ! 1) (3) Pre-stage operational amplifier block (VST = 5V, VMT = 0V, RL ! OFF) 667 Optical disc ICs Application example 668 BA5972FP Optical disc ICs FOperation notes (1) The BA5972FP contains a thermal shutdown circuit. When the chip temperature reaches 175_C (Typ.), the output current is muted. If the chip temperature then drops below 150_C (Typ.), then the mute is released. (2) By having the mute pin (pin 7) voltage pulled up to 2.0V or greater, you can mute the output current for channels 1 and 4. For normal conditions, have pin 7 open or at 0.5V or below. (3) If the voltage of the bias pin (pin 1) drops below 1.4V (Typ.), outputs are muted. For normal conditions, have the voltage above 1.7V. (4) If the power supply voltage drops below 3.8V (Typ.), internal circuits turn off. If the power supply voltage then rises to 4.0V (Typ.), the circuits turn on. (5) If the voltage of the thermal shutdown, mute ON, or bias pin drops, or if the power supply voltage drops, the mute is activated; however, in these situations, only the drivers are muted. Also, the output pin voltage becomes the internal bias voltage (approx. VCC / 2). BA5972FP (6) If the standby pin voltage is open or 0.5V or below, the circuit current enters the standby condition. For normal operation, have the standby pin voltage pulled up to 2.0V or greater. (7) Connect a bypass capacitor (approx. 0.1µF) between the bases of the power supply pins of this IC. (8) Even though the radiation fins are connected to ground within the package, be sure to also connect them to a ground externally as well. (9) The application example will assure excellent results, but nevertheless, be sure to carefully check all characteristics during use. During use with constants in the external circuitry modified, be sure to leave a sufficient margin in order to take into consideration fluctuations in the static and transient characteristics of the external components and this IC. Also, be aware that ROHM has not sufficiently performed all confirmations regarding patent rights. FElectrical characteristic curves 669 Optical disc ICs External dimensions (Units: mm) 670 BA5972FP