379

Optical disc ICs

BA6798S

FApplication example

FOperation notes

(1)

The BA6798S has an internal thermal shutdown cir-

cuit. Output current is muted when the chip temperature

exceeds 175

_C (typically).

(2)

If the mute pin (pin 6) voltage is opened or lowered

below 0.5V, the output current will be muted. Pin 6 should

be pulled up above 2.0V during normal use.

(3)

The bias pin (pin 17) 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 volt-

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

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

(5)

The driver circuit shuts down when the supply volt-

age drops below 4.5V (typically), and starts up again

when the voltage rises above 4.7V (typically).

(6)

Be sure to connect the IC to a 0.1

µF bypass capaci-

tor to the power supply, at the base of the IC.

(7)

The capacitor between regulator output (pin 7) and

GND also serves to prevent oscillation of the IC, so select

one with good temperature characteristics.