AP3591

Document number: DS36906 Rev. 1 - 2

3 of 18

www.diodes.com

March 2014

© Diodes Incorporated

AP3591

A Product Line of

Diodes Incorporated

Pin Descriptions

Pin Number

Pin Name

Function

1

EN/DEM

Enable/Diode Emulation Mode control input. Connect to VDD for DEM mode;

connect to GND for shutdown and float the pin for CCM mode

2

TON

On time/Frequency adjustment pin. Connect to PHASE through a resistor. TON

is an input for the PWM controller

3

VOUT

Output voltage pin. Connect to the output of PWM converter. VOUT is an input

for the PWM controller

4

VDD

Analog supply voltage input for the internal analog integrated circuit. Bypass to

GND with a 1µF ceramic capacitor

5

FB

Feedback input pin. Connect FB pin to a resistor voltage divider from VOUT to

6

PGOOD

Power good signal open-drain output for PWM converter. This pin will be pulled

high when the output voltage is within the target range

7

GND

Analog Ground

8

PGND

Power Ground

9

LGATE

Low-side N-MOSFET gate driver output for the PWM converter. This pin swings

between PGND and VDDP

10

VDDP

VDDP is the gate driver supply for external MOSFETs. Bypass to GND with a

1µF ceramic capacitor

11

CS

Over current trip point set input. Connect a resistor from this pin to signal ground

to set threshold for both over current limit and negative over current limit

12

PHASE

The UGATE High-side gate driver return. Also serves as anode of over current

comparator

13

UGATE

High-side N-MOSFET floating gate driver output for the PWM converter. This pin

swings between PHASE and BOOT

14

BOOT

Bootstrap pin. A bootstrap capacitor is connected for PWM converter. Connect

to an external ceramic capacitor to PHASE

–

Exposed Pad

The exposed pad must be soldered to a large PCB and connected to GND for

maximum power dissipation