Rohm BA6791FP 4-channel btl driver for cd player Datasheet

Optical disc ICs
4-channel BTL driver for CD players
BA6790FP / BA6791FP
The BA6790FP and BA6791FP are 4-channel BTL drivers for CD player actuators and motors. These ICs have internal
5 V regulators and general purpose operational amplifiers, and are mounted to a 28-pin HSOP package, allowing for
the miniaturization of applications.
Applications
CD players and portable CD
Features
1) 4-channel BTL driver.
2) HSOP 28-pin package allows for miniaturization of
applications.
3) Wide dynamic range. (typically 5.4V when VCC = 8V
and RL = 8Ω)
Block diagram
348
4) Internal thermal shutdown circuit.
5) Gain is adjustable with a single attached resistor.
6) Internal 5V regulator. (requires attached PNP transistor)
7) Internal general purpose operational amplifier.
Optical disc ICs
BA6790FP/BA6791FP
FPin descriptions
FAbsolute maximum ratings (Ta = 25_C)
FRecommended operating conditions
349
Optical disc ICs
BA6790FP/BA6791FP
FElectrical characteristics (unless otherwise noted, Ta = 25_C, VCC = 8V, f = 1kHz, RL = 8Ω)
350
Optical disc ICs
BA6790FP/BA6791FP
Measurement circuit
351
Optical disc ICs
Measurement circuit switch table
Input / output circuits
352
BA6790FP/BA6791FP
Optical disc ICs
BA6790FP/BA6791FP
Application example
353
Optical disc ICs
FThermal derating curve
FExternal dimensions (Units: mm)
354
BA6790FP/BA6791FP
FOperation notes
(1) The BA6790FP and BA6791FP have an internal
thermal shutdown circuit. Output current is muted when
the chip temperature exceeds 175_C (typically) and restored when the chip temperature falls to 150_C (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. In each case,
only the drivers are muted. During muting, the output pins
remain at the internal bias voltage, roughly (VCC / 2).
(5) Be sure to connect the IC to a 0.1µF bypass capacitor to the power supply, at the base of the IC.
(6) The radiating fin is connected to the packages internal GND, but should also be connected to an external
ground.
(7) The capacitor between regulator output (pin 6) and
GND also serves to prevent oscillation of the IC, so select
one with good temperature characteristics.
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