Rohm BA6796 5-channel btl driver for cd player Datasheet

Optical disc ICs
5-channel BTL driver for CD players
BA6796FP
The BA6796FP, an IC designed for CD and MD players, has a 5-channel BTL power driver and a standard operational
amplifier. The spindle and tray driver share a single output buffer, and are specified with a control pin. In addition, the
internal level shift circuit reduces the number of attached components.
Applications
CD players, CD-ROM drives, MD players and other optical disc devices
Features
1) 5-channel BTL driver in a 28-pin HSOP package, allowing for application miniaturization.
2) The five drivers are turned on and off according to
control pin logic combinations.
3) The tray driver operates even when the servo power
supply drops.
4) Internal thermal shutdown circuit.
5) Gain is adjustable with an attached resistor.
6) Internal standard operational amplifier.
Absolute maximum ratings (Ta = 25C)
Recommended operating conditions (Ta = 25C)
483
Optical disc ICs
Block diagram
484
BA6796FP
Optical disc ICs
BA6796FP
Pin descriptions
485
Optical disc ICs
Input / output circuits
486
BA6796FP
Optical disc ICs
BA6796FP
Electrical characteristics (unless otherwise noted, Ta = 25C, VCC = 8V, f = 1kHz, RL = 8Ω)
487
Optical disc ICs
Measurement circuit
488
BA6796FP
Optical disc ICs
BA6796FP
Measruement circuit switch table
489
Optical disc ICs
Function description
CTL and CTL2
F and R (channel 5 control enabled only when channel 5 is on)
490
BA6796FP
Optical disc ICs
BA6796FP
Application example
491
Optical disc ICs
BA6796FP
Operation notes
(1) Setting the tray motor driver voltage (forward mode)
(2)
Mute functions
Thermal shutdown
The output current is muted when the chip temperature
exceeds 175C (typically).
Supply voltage drop muting
The internal circuits turn off when the supply voltage
drops below 4.3V (typically), and turn on again when it
rises above 4.5V (typically).
Electrical characteristic curves
492
Bias drop muting
Muting also occurs when the bias pin voltage (26 pin) is
lowered below 1.4V (typically). Be sure the voltage stays
between 1.6V and 6.5V during normal operation.
(3) Muting occurs during thermal shutdown and when
the supply voltage or bias pin voltage drops. In each
case, only the driver is muted. The output pin voltage during muting is the internal bias voltage, roughly VCC–
VF / 2.
(4) Attach a 0.1µF bypass capacitor to the power supply, at the base of the IC.
(5) Connect the radiating fin to an external ground.
Optical disc ICs
BA6796FP
External dimensions (Units: mm)
493
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