AP3581A/B/C

Document number: DS41552 Rev. 2 - 4

1 of 13

www.diodes.com

November 2018

© Diodes Incorporated

AP3581A/B/C

PART OBSOLETE

– NO ALTERNATE PART

SINGLE PHASE SYNCHRONOUS BUCK PWM CONTROLLER

Description

The1AP3581A/B/C1is1a1compact1synchronous

–

rectified

bulk

controller specifically designed to operate from 5V/12V supply and

deliver high-quality output voltage as low as 0.6V (AP3581A) or 0.8V

(AP3581B/C). The AP3581A/B/C operates at fixed frequency of

300kHz (AP3581A/B) or 200kHz (AP3581C) and provides an optimal

level of integration to reduce size and cost of the power supply.

This controller integrates internal MOSFET drivers that support

12V+12V bootstrapped voltage for high- efficiency power conversion.

The bootstrap diode is built-in to simplify the circuit design and

minimize external part count.

This controller provides single feedback loop, voltage-mode control

with fast transient response. The error amplifier features a 10MHz

gain-

bandwidth product and 6V/μs slew rate which enables high

converter bandwidth for fast transient performance.

Other features include internal soft-start, under voltage protection,

over current protection and shutdown function. With afore-mentioned

functions, this part provides customers a compact, high efficiency,

well-protected and cost-effective solutions.

The AP3581A/B/C is available in PSOP-8 package.

Features



Supply Voltage: 5V/12V

VIN Input Range: 3.0V to 13.2V

0.6V/0.8V to 80% of VIN Output Range

Internal Reference: 0.6V/0.8V



Simple Single-Loop Control

Voltage-Mode PWM Control

Duty Cycle: 0% to 80%

Fast Transient Response



10MHz High-Bandwidth

Error Amplifier with 6V/μs Slew Rate



Fixed Oscillator Frequency: 300kHz/200kHz



Lossless, Programmable Over Current Protection

(Uses Lower MOSFET RDS(ON) )



Start-Up into Pre-biased Output



Built-In Thermal Shutdown



Built-In Soft-Start



Over Current/Voltage Protection



Under Voltage Protection



Integrated Boot Diode

Pin Assignments

(Top View)

1

2

3

4

8

7

6

5

BOOT

UGATE

OPS

LGATE

PHASE

COMP/EN

FB

VCC

GND

9

PSOP-8

(Top View)

Applications



Power Supplies for Microprocessors/Peripherals

PCs, Embedded Controllers, Memory Supplies

DSP and Core Communications Processor Supplies



Subsystem Power Supplies

PCI, AGP, Graphics Cards, Digital TV

SSTL-2 and DDR/2/3 SDRAM Bus Termination Supply



Cable Modems, Set Top Boxes, and DSL Modems



Industrial Power Supplies and General Purpose Supplies



5V/12V Input DC-DC Regulators



Low-Voltage Distributed Power Supplies