Optical disc ICs 4-channel BTL driver for CD player and CD-ROM drives BA5921FP The BA5921FP is an IC with an internal 4-channel BTL driver for CD players and CD-ROM driver actuators and motors, as well as an internal standard operational amplifier. In addition, the 28-pin HSOP package allows for application miniaturization. Applications CD players, CD-ROM drives Features 1) 4-channel BTL driver. 2) HSOP 28-pin power package allows for application miniaturization. 3) Wide dynamic range. (typically 3.6V when VCC = 5V and RL = 8Ω) 4) 5) 6) 7) Internal thermal shutdown circuit. Gain is adjustable with an attached resistor. Internal standard operational amplifier. Output current is mutable with an external mute pin. Absolute maximum ratings (Ta = 25C) Recommended operating conditions (Ta = 25C) 269 Optical disc ICs Block diagram Pin descriptions 270 BA5921FP Optical disc ICs BA5921FP Pin equivalent circuit diagrams 271 Optical disc ICs Electrical characteristics (unless otherwise noted, Ta = 25C, VCC = 5V, BIAS = 2.5V, RL = 8Ω) 272 BA5921FP Optical disc ICs BA5921FP Measurement circuit 273 Optical disc ICs Measurement circuit switch table (1) Driver (OPIN1, NF1, OPRL1, VOPIN = 2.5V) (2) Operational amplifier (RLOFF) 274 BA5921FP Optical disc ICs BA5921FP Application example 275 Optical disc ICs Operation notes (1) The BA5921FP has a thermal shutdown circuit. The output current is muted when the chip temperature rises above 175C (typically). When the chip temperature falls to 150C (typically), the driver circuit starts up again. (2) The output current can be muted by opening the mute pin (pin 9) or lowering it below 0.5V. During ordinary use, pin 9 should be pulled up above 2.0V. (3) Muting also occurs when the bias pin (pin 2) drops below 1.4V (typically). Make sure it stays above 1.7V during normal use. Electrical characteristic curves 276 BA5921FP (4) The internal circuits turn off when the supply voltage drops below 3.8V (typically), and turn on again when it rises above 4.0V (typically). (5) Muting occurs during thermal shutdown, mute-on operations or a drop in the bias pin voltage or supply voltage. In each case, only the drivers are muted. During muting, the output pins remain at the internal bias voltage, roughly (VCCVF) / 2. (6) Connect the IC to a 0.1µF bypass capacitor between power supplies, at the base of the IC. (7) The radiating fin is connected to the package’s internal GND, but should also be connected to an external ground. Optical disc ICs BA5921FP External dimensions (Units: mm) 277