UA8888S

LINEAR INTEGRATED CIRCUIT

UNISONICTECHNOLOGIESCO.,LTD

6 of 8

www.unisonic.com.tw

QW-R109-015,B

OPERATION NOTES

(1) The thermal shutdown function will be triggered while the chip junction temperature reach 150

typical,

℃

and

then the output current is muted. The hysteresis is set to 25

ty

℃

pical, so the circuit will start up again when the

chip temperature falling to 125℃ typical.

(2) In case mute pin voltage is under 0.5V or NC, output current is muted except for tray motor driver. Mute pin

voltage should be more than 2.0V for normal application.

(3) Pin 27(Bias pin) should be pulled up to more than 1.2V. In case the bias pin voltage is pulled down below

0.9V(typ.), the output current is muted.

(5) Ground-plane wiring up to GND is performed and should tightly connect to external GND.

(6) Pin 20 and 24 should be floated due to reserve for internal test only.

(7) When Vcc1 voltage drop to below 3.8V, schematic is muted. The schematic will return to work when Vcc1 rise

up with a hysterisis of 0.3V(typ.)

(8) Tray driver logic input:

FWD (pin6)

REV (pin7)

Function

L

L

OPEN

OPEN

Open mode

L

H

L

H

Reverse mode

H

L

H

L

Forward mode

H

H

L

L

Brake mode

Pin 6 and Pin 7 are designed to avoid simultaneous activation of upper and lower output transistors, however, in

order to improve reliability, apply motor forward/reverse input once through open mode.

We recommend time period for open longer than 10msec.