Optical disc ICs 4-channel H-bridge type BTL driver for CD players BA6892FP The BA6892FP is a 4-channel H-bridge BTL driver for CD players. Independent power supplies for each predriver and power driver assure efficient operation at low voltages. Each channel is independently mutable. Applications CD players, CD-ROM drives and other optical disc devices Features 1) 4-channel BTL driver in a HSOP 28-pin package, ideal for application miniaturization. 2) Wide dynamic range. 3) Driver gain is adjustable with an attached resistor. 4) Independent power supply for each preamplifier and power amplifier, for drives that operate efficiently on low voltages. 5) Power amplifier current drops to an extremely low level when the preamplifier power supply is lowered, allowing for a standby mode. Absolute maximum ratings (Ta = 25C) Recommended operating conditions (Ta = 25C) 445 Optical disc ICs Block diagram 446 BA6892FP Optical disc ICs BA6892FP Pin descriptions 447 Optical disc ICs Input / output circuits 448 BA6892FP Optical disc ICs BA6892FP Electrical characteristics (unless otherwise noted, Ta = 25C, VCCPRE = VCCPOW = 4V, BIAS = 2V, RL = 8Ω, RIN = 9.1kΩ) 449 Optical disc ICs Measurement circuit 450 BA6892FP Optical disc ICs BA6892FP 451 Optical disc ICs Application example 452 BA6892FP Optical disc ICs Operation notes (1) The BA6892FP has an internal thermal shutdown circuit. Output current is muted when the chip temperature exceeds 175C (typically) and restored when the chip temperature falls to 150C (typically). (2) The mute pin operates normally when open and at the LOW level (below 0.5V), but mutes the output when raised to the HIGH level (above 2V). A high impedance is output during muting. The mute pin functions independently for each channel. (3) Dead zone width is determined as follows: Dead zone width = input resistance (attached resistor + BA6892FP internal input resistor 1kΩ) 0.2µA Dead zone width various according to the gain setting as defined in the preceding equation. Example: When attached input resistor = 9.1kΩ, VDB = (9.1k+1k) 0.2µ 2mV Output pins output high impedance in a dead zone equal to AmV (total for positive and negative). (4) Be sure to connect the IC to a 0.1µF bypass capacitor to the power supply, at the base of the IC. (5) Connect the radiating fin to an external ground. Electrical characteristic curves 453 Optical disc ICs External dimensions (Units: mm) 454 BA6892FP