AP3583/A

Document number: DS41575 Rev. 3- 2

2 of 12

www.diodes.com

November 2018

© Diodes Incorporated

AP3583/A

Typical Applications Circuit

VCC

BOOT

UGATE

LGATE

PHASE

OPS

REFIN

FB

Enable

Disable

R1

10k

R2

10k

GND

VIN=12V

VOUT=1.2V

Q1

Q2

Q3

L1

1.0

μH

C5

1000

μF/6.3V

C6

1000

μF/6.3V

R3

C3 1

mF

C4

0.1

mF

C1

10

μF/25V

C2

220

μF/25V

Reference

Input

R4 2

W

1

2

3

4

5

6

7

8

9

Pin Descriptions

Pin Number

Pin Name

Function

1

BOOT

Bootstrap pin. Connect a bootstrap capacitor (Typically from 0.1 to 0.47

μF) from this pin to

PHASE pin to create a BOOT voltage suitable to drive a standard N-Channel MOSFET.

2

UGATE

Upper-gate drive pin. Connect this pin to the upper MOSFET gate providing the gate drive.

This pin is monitored by the adaptive shoot-through protection circuitry to determine when the

upper MOSFET has been turned off.

3

OPS

Over-current setting pin. Connecting a resistor (ROCSET) between OPS and GND to set the

over-current trigger point.

4

LGATE

Lower-gate drive pin. Connect LGATE to the lower MOSFET gate providing the gate drive for

the lower MOSFET. This pin is monitored by the adaptive shoot-through protection circuitry to

determine when the lower MOSFET has been turned off.

5

VCC

Bias supply pin. Provides a 5V or 12V bias supply for the chip from this pin. The pin should

be bypassed with a capacitor to GND.

6

FB

Feedback pin. This pin is the inverting input of the internal error amplifier. A resistor divider

from output to GND is used to set the output voltage.

7

REFIN

External reference input pin. This pin receives a voltage with range from 0.4V to 3.0V as the

reference voltage at the non-inverting input of the error amplifier. Pull this pin lower than 0.3V

to disable the controller, and the VUGATE and VLGATE will go low. Let this pin open for internal

0.6V reference use.

8

PHASE

PHASE pin. This pin connects to the source of the upper MOSFET and the drain of the lower

MOSFET. This pin is also monitored by the adaptive shoot-through protection circuitry to

determine when the upper MOSFET is turned off.

9

GND

Exposed pad as ground pin. Represents the signal and power ground for the IC. Tie this pin

to ground island/plane through the lowest impedance connection available.