APR34509 SECONDARY SIDE SYNCHRONOUS RECTIFICATION SWITCHER Description Pin Assignments The APR34509 is a secondary side Combo IC, which combines an N- (Top View) Channel MOSFET and a driver circuit designed for Synchronous Rectification (SR), supports CCM, DCM and Quasi-Resonant Flyback Topologies. DRISR GND 1 8 GND The N-Channel MOSFET is optimized for low gate charge, low VCC 2 7 R , fast switching speed and body diode reverse recovery DS(ON) CCM AREF 3 6 performance. DRAIN 5 VDET 4 The synchronous rectification can effectively reduce the secondary side rectifier power dissipation and provide high performance solution. By sensing MOSFET drain-to-source voltage, the APR34509 can Note: The DRAIN pin of internal MOSFET is exposed PAD, which is at the bottom of IC (the dashed box). The secondary current should flow from GND (pins 7 and output ideal drive signal with less external components. 8) to this exposed PAD. It can provide high performance solution for 5V to 12V output voltage SO-8EP application. The APR34509 is available in SO-8EP package. Features Applications Synchronous Rectification for DCM Operation Flyback Adapters/Chargers for Cell/Cordless Phones, ADSL Modems, MP3 and Other Portable Apparatus Eliminate Resonant Ring Interference Standby and Auxiliary Power Supplies Fast Detector of Supply Voltages Fewest External Components Moisture Sensitivity: MSL Level 3 per J-STD-020 Terminals: Finish Matte Tin Plated Leads, Solderable per M2003 JESD22-B102 Weight: 0.081 grams (Approximate) 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. APR34509 Typical Applications Circuit C21 C22 + + C23 R21 D1 Primary Q1 Control C Y APR34509 IC R1 DRAIN GND DRAIN R23 R24 GND DRISR VDET VCC R2 C24 AREF CCM C CCM R3 R C AREF AREF ZD1 Pin Descriptions Pin Number Pin Name Function 1 DRISR Synchronous rectification MOSFET drive. 2 VCC Power supply, connected with system output. 3 CCM Primary trigger signal sense input. Synchronous rectification sense input and dynamic function output, connected to DRAIN 4 VDET through a resistor. 5 DRAIN Drain pin of internal MOSFET. The Drain voltage signal can obtain from this pin. Program a voltage reference with a resistor from AREF to GND, to enable synchronous 6 AREF rectification MOSFET drive signal. 7, 8 GND Source pin of internal MOSFET, connected to Ground. Drain pin of internal MOSFET. The secondary current should flow from GND (Pins 7 and 8) Exposed PAD DRAIN to this DRAIN pad. 2 of 13 APR34509 March 2020 Diodes Incorporated www.diodes.com Document number: DS38510 Rev. 3 - 2