Optical disc ICs 4-channel BTL driver for CD-ROM drives BA5952AFP The BA5952AFP is a four-channel BTL driver IC for driving the motors and actuators in products such as CD ROM drives. Two of the channels use current feedback to minimize the current phase shift caused by the influence of load inductance. Applications CD-ROM drives, DVD drives, DVD ROM drives. Features 1) Two channels are current-drive-type BTL drivers for two-shaft actuators. One channel is a voltage-drivetype BTL driver for transport motors, and the last is a current-drive-type BTL driver for loading motors. 2) Wide dynamic range (4.0V (typ.) when PreVCC = 12V, PVCC = 5V, and RL = 8). 3) Level shift circuit on chip. 4) Thermal shutdown circuit on chip. Absolute maximum ratings (Ta = 25C) Recommended operating conditions (Ta = 25C) 542 * Dual-shaft actuator drivers These drivers use current feedback to minimize the current phase shift cause by the influence of load inductance. Output structure is power op-amp to minimize back-rush noise. * Transport motor driver Differential input and signal addition is possible by connecting general-purpose op-amps to the inputs. * Loading driver Performs forward and reverse drive with transistor logic input. Can also be used as a linear BTL driver. Optical disc ICs BA5952AFP Block diagram Pin descriptions 543 Optical disc ICs Input/output circuits 544 BA5952AFP Optical disc ICs BA5952AFP Electrical characteristics (unless otherwise noted, Ta = 25C, PreVCC = 12V, PVCC1 = PVCC2 = 5V, Electrical characteristics (BIAS = 2.5V, RL = 8, Rd = 0.5, C = 100pF) 545 Optical disc ICs Measurement circuit 546 BA5952AFP Optical disc ICs BA5952AFP Application example 547 Optical disc ICs Operation notes (1) This IC has a built in thermal shutdown circuit that mutes the output current when the chip temperature reaches 175C (typ.). The hysteresis is set to 25C (typ.), so the driver circuits start up again when the chip temperature falls to 150C (typ.). (2) The driver buffer is switched off when the supply voltage falls below 3.8V (typ.), and is switched back on when the voltage reaches 4.0V (typ.) again. (3) The mute circuit logic is active low. (4) Mute is applied when the buffer pin voltage falls below 1.4V (typ.). Normally, operate with this at 1.8V at least. Electrical characteristics curves 548 BA5952AFP (5) Connect a bypass capacitor between the bases of the power supply pins of this IC. Supplement Current-feedback driver The transmission gain (output current/input voltage) is given by: gm = 1 (A / V) RdRWIRE RWIRE is the total gold wire resistance inside the package (0.15 0.05) (typ.). Optical disc ICs BA5952AFP External dimensions (Units: mm) 549