Rohm BA6795FP 5-channel btl driver for cd player Datasheet

Optical disc ICs
5-channel BTL driver for CD players
BA6795FP
The BA6795FP is a 5-channel BTL power driver for CD players and has an internal 5V regulator (attached PNP transistor
required). The loading and spindle motor output pins are dual-use output pins and are switched between drivers using
a control input. In addition, the internal level shifting circuit reduces the number of external components.
Applications
CD players, CD-ROM drives and other optical disc devices
Features
1) 5-channel BTL driver in a HSOP 28-pin package,
ideal for application miniaturization.
2) Internal level shifting circuit reduces the number of
external components.
Absolute maximum ratings (Ta = 25C)
Recommended operating conditions (Ta = 25C)
472
3) Gain is adjustable with an attached resistor.
4) Internal thermal shutdown circuit.
5) Internal 5V regulator. (attached PNP transistor required)
Optical disc ICs
BA6795FP
Block diagram
473
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Pin descriptions
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BA6795FP
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BA6795FP
Electrical characteristics (unless otherwise noted, Ta = 25C, VCC = 8V, f = 1kHz, RL = 8Ω)
475
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Measruement circuit
476
BA6795FP
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BA6795FP
Measruement circuit switch table
477
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Circuit operation
(1) Switching between spindle and loading motor driver output modes (VCC = 8V)
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BA6795FP
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BA6795FP
Circuit operation
(2) Loading motor driver voltage setting (forward mode)
479
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Application example
480
BA6795FP
Optical disc ICs
Operation notes
(1) The BA6795FP has an internal thermal shutdown
circuit. Output current is muted when the chip temperature exceeds 175C (typically).
(2) If the mute pin (pin 7) voltage is opened or lowered
below 0.5V, the output current will be muted. Pin 7 should
be pulled up above 2.0V during normal use.
(3) The bias pin (pin 23) is muted when lowered below
1.4V (typically). Make sure it stays above 1.6V during
normal use.
(4) 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 (VCC–VF) / 2.
BA6795FP
(5) The driver circuit shuts down when the supply voltage drops below 4.3V (typically), and starts up again
when the voltage rises above 4.5V (typically).
(6) Fluctuation due to temperature occurs in the gain
when using an attached resistor as the input resistor for
a driver other than the spindle driver (typically 2200ppm
per degree) or for the spindle driver (typically 4600ppm
per degree. (Only when using the gain adjustment pin.)
(7) Be sure to connect the IC to a 0.1µF bypass capacitor to the power supply, at the base of the IC.
(8) The radiating fin is connected to the package’s internal GND, but should also be connected to an external
ground.
(9) The capacitor between regulator output (pin 6) and
GND also serves to prevent oscillation of the IC, so select
one with good temperature characteristics.
Electrical characteristic curves
481
Optical disc ICs
External dimensions (Units: mm)
482
BA6795FP
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