Optical disc ICs
FOperation
notes
(1) The BA5970FP contains a thermal shutdown cir-
cuit. When the chip temperature reaches 175_C (Typ.),
the output current is muted. If the chip temperature then
drops below 150_C (Typ.), then the mute is released.
(2) By having the mute pin voltage pulled up to 2.0V or
greater, you can mute the output current. For normal
conditions, have mute pin open or at 0.5V or below. (Pin
9 mutes channels 1 and 2, and pin 20 mutes channels 3
and 4.)
(3) If the voltage of the bias pin (pin 1) drops below 1.4V
(Typ.), outputs are muted. For normal conditions, have
the voltage above 1.7V.
(4) If the power supply voltage drops below 3.8V (Typ.),
BA5970FP
internal circuits turns off. If the power supply voltage then
rises to 4.0V (Typ.), the circuits turn on.
(5) If the voltage of the thermal shutdown, mute ON, or
bias pin drops, or if the power supply voltage drops, the
mute is activated; however, in these situations, only the
drivers are muted. Also, the output pin voltage becomes
the internal bias voltage (approx. V
CC
/ 2 for channels 1
and 2, and (V
CC
–VF) / 2 for channels 3 and 4).
(6) Connect a bypass capacitor (approx. 0.1µF) be-
tween the bases of the power supply pins of this IC.
(7) Even though the radiation fins are connected to
ground within the package, be sure to also connect them
to a ground externally as well.
FElectrical
characteristic curves
660
ROHM [ ROHM ]
