680

Optical disc ICs

BA6898S/BA6898FP

FOperation notes (pin Nos. are those for the BA6898S)

(1)

Relationship between mute and reset output

Regulator voltage drop

If the regulator voltage drops to 4.0V (Typ.) or below, the reset output turns low and the

. . . . .

mute turns on. If the voltage then rises again to 4.2V (Typ.), the reset output turns high

and the mute turns off.

Bias voltage drop

If the bias pin (pin 3) voltage lowers to 1.4V (Typ.) or below, the mute turns on and the

. . . . . . . . . .

reset output turns low. For normal operations, have the voltage at 1.6V or greater.

Thermal shutdown

When the chip temperature reaches 175

_C (Typ.), the mute turns on and the reset output

. . . . . . . . .

turns low. If the chip temperature then drops below 150

_C (Typ.), then the mute turns off

and the reset output turns high.

Mute (pin 15)

If the mute pin (pin 15) voltage is open or lowers to 0.5V or below, the mute turns on but

. . . . . . . . . . . . .

the reset output does not change.

(2)

If the voltage of the thermal shutdown, mute ON, or

bias pin drops, or if the regulator voltage drops, the mute

is activated; however, in these situations, only the drivers

are muted. Also, the output pin voltage becomes the in-

(3)

Connect a bypass capacitor (approx. 0.1

µF) be-

tween the bases of the power supply pins of this IC.

(4)

Even though pins 16 and 32 are connected to

ground within the package, be sure to also connect them

to a ground externally as well.

(5)

The capacitor connected between the regulator

output pin (pin 14) and GND also serves to prevent os-

cillation, so be sure to use a capacitor with excellent ther-

mal characteristics.

(6)

If the regulator is not used, short the regulator out-

connected transistor base (pin 13) open.

(7)

Of the ground pins, only pin 18 is not connected to

the IC substrate. Therefore, design the PC board pattern

so that the potential of GND pin 18 does not go below the

substrate GND (including transient conditions).

FElectrical characteristic curves