UA8888S
LINEAR INTEGRATED CIRCUIT
UNISONIC TECHNOLOGIES CO., LTD
www.unisonic.com.tw
6 of 8
QW-R109-015,B
OPERAT ION NOT ES
(1) The thermal shutdown function will be triggered while the chip junction temperature reach 150
then the output current is muted. The hysteresis is set to 25
chip temperature falling to 125
typical.
typical, and
typical, so the circuit will start up again when the
(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.
(4) Insert the bypass capacitor (~0.1
μ
F) between V
CC
pin and GND pin as close as possible.
(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)
L
L
H
H
REV (pin7)
L
H
L
H
V
OTR+
(pin10)
OPEN
L
H
L
V
OTR-
(pin9)
OPEN
H
L
L
Function
Open mode
Reverse mode
Forward mode
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.
The voltage between “H” side and “L” side output voltage is equal to three times(9.2dB Typ.) V
TCL
voltage(Pin21).
And the “H” side and “L” side output voltage both equal to V
CC
/2 when in open mode and brake mode.