Optical disc ICs
FOperation
notes
(1) The BA5972FP 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 (pin 7) voltage pulled up to
2.0V or greater, you can mute the output current for chan-
nels 1 and 4. For normal conditions, have pin 7 open or
at 0.5V or below.
(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.),
internal circuits turn 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).
BA5972FP
(6) If the standby pin voltage is open or 0.5V or below,
the circuit current enters the standby condition.
For normal operation, have the standby pin voltage
pulled up to 2.0V or greater.
(7) Connect a bypass capacitor (approx. 0.1µF) be-
tween the bases of the power supply pins of this IC.
(8) Even though the radiation fins are connected to
ground within the package, be sure to also connect them
to a ground externally as well.
(9) The application example will assure excellent re-
sults, but nevertheless, be sure to carefully check all
characteristics during use. During use with constants in
the external circuitry modified, be sure to leave a suffi-
cient margin in order to take into consideration fluctua-
tions in the static and transient characteristics of the ex-
ternal components and this IC.
Also, be aware that ROHM has not sufficiently performed
all confirmations regarding patent rights.
FElectrical
characteristic curves
669
ROHM [ ROHM ]
