276

Optical disc ICs

BA5921FP

FOperation notes

(1)

The BA5921FP has a thermal shutdown circuit.

The output current is muted when the chip temperature

rises above 175

_C (typically). When the chip tempera-

ture falls to 150

_C (typically), the driver circuit starts up

again.

(2)

The output current can be muted by opening the

mute pin (pin 9) or lowering it below 0.5V. During ordinary

use, pin 9 should be pulled up above 2.0V.

(3)

Muting also occurs when the bias pin (pin 2) drops

below 1.4V (typically). Make sure it stays above 1.7V dur-

ing normal use.

(4)

The internal circuits turn off when the supply volt-

age drops below 3.8V (typically), and turn on again when

it rises above 4.0V (typically).

(5)

Muting occurs during thermal shutdown, mute-on

operations or a drop in the bias pin voltage or supply volt-

age. In each case, only the drivers are muted. During

muting, the output pins remain at the internal bias volt-

*VF)/2.

(6)

Connect the IC to a 0.1

µF bypass capacitor be-

tween power supplies, at the base of the IC.

(7)

The radiating fin is connected to the package’s in-

ternal GND, but should also be connected to an external

ground.

FElectrical characteristic curves