Diodes AP1539 - Manual (Page 3)

AP1539
18V 4A 300KHz BUCK CONVERTER
AP1539 Rev. 4 3 of 13 OCTOBER 2009
DS31477 www.diodes.com © Diodes Incorporated
Pin Descriptions
Pin Name Pin No. Description
FB 1 Feedback pin
EN 2
Power-off pin
H: Normal operation (Step-down operation)
L: Step-down operation stopped (All circuits deactivated)
OCSET 3 Add an external resistor to set max output current
V
CC
4 IC power supply pin
Output 5, 6
Switch Pin. Connect external inductor/diode here. Minimize trace area
at this pin to reduce EMI
V
SS
7, 8 GND Pin
Block Diagram
Oscillation
Circuit
Reference Voltage
Source with Soft Start
PWM-Switched
Control Circuit
+
-
Vss V
EN
EN
90uA
OCSET
FB
Vcc
Thermal
Shutdown
Output