APR349

Document number: DS43554 Rev. 2 - 2

1 of 10

www.diodes.com

July 2021

© Diodes Incorporated

APR349

SECONDARY SIDE SYNCHRONOUS RECTIFICATION CONTROLLER

Description

The APR349 is a secondary-side MOSFET driver for synchronous

rectification, which can effectively reduce the secondary-side rectifier

power dissipation and provide a high-performance solution.

The APR349 supports continuous or discontinuous conduction mode

(CCM and DCM) and quasi-resonant flyback operation. It utilizes an

intelligent control method to realize on-time control, which not only

provides a short turn-on and turn-off delay to reduce power loss, but

also eliminate the false trigger of resonant ring and keep safe

operation without adding any external components or circuitry.

The APR349 can be charged by internal PLR (Pulse Linear

Regulator) at low system output voltage, and provide a wide output

operation voltage from 3.3V to 24V.

The APR349 is available in SOT26 (Type CJ) package.

Features



Support Flyback Synchronous Rectification with CCM/DCM/QR

Operation Mode



Intelligent Control to Minimize Turn-On and Turn-Off Delay



Smart-Blanking Control to Prevent Shoot-Through



Supports Both High-Side and Low-Side Application



Built-in PLR Power Supply for Low System Output Voltage



Internal UVLO Protection



Fewest External Components



Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2)



Halogen and Antimony Free. “Green” Device (Note 3)



For automotive applications requiring specific change

control (i.e. parts qualified to AEC-Q100/101/200, PPAP

capable, and manufactured in IATF 16949 certified facilities),

please contact us or your local Diodes representative.

https://www.diodes.com/quality/product-definitions/

Pin Assignments

(Top View)

SOT26 (Type CJ)

Applications



Adaptive Chargers for Cellular Phones, Digital Cameras, and

Power Tools



AC/DC Adapters



Battery-Powered Systems



All SMPS with High-Efficiency Requirements

Notes:

1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS), 2011/65/EU (RoHS 2) & 2015/863/EU (RoHS 3) compliant.

2. See https://www.diodes.com/quality/lead-

free/ for more information about Diodes Incorporated’s definitions of Halogen- and Antimony-free, "Green" and

Lead-free.

3. Halogen- and Antimony-

free "Green” products are defined as those which contain <900ppm bromine, <900ppm chlorine (<1500ppm total Br + Cl) and

<1000ppm antimony compounds.

Typical Applications Circuit

VOUT

VOUT

GND

Rx

VDD

GATE

DRAIN

APR349

Q1

Rx

C1

Q2

C2

Low-Side Application

High-Side Application

1

2

3

4

5

6

VDD

GND

GATE

VOUT

DRAIN

Rx

VOUT

VOUT

GND

Rx

VDD

GATE DRAIN

APR349

Q1

Q2

R1

C1

C2