NCP4308 Synchronous Rectifier Controller The NCP4308 is a synchronous rectifier controller for switch mode power supplies. The controller enables high efficiency designs for flyback, quasi resonant flyback and LLC topologies. www.onsemi.com Externally adjustable minimum offtime and ontime blanking periods provides flexibility to drive various MOSFET package types and PCB layout. A reliable and noise less operation of the SR system is MARKING insured due to the Self Synchronization feature. The NCP4308 also DIAGRAMS utilizes Kelvin connection of the driver to the MOSFET to achieve high 8 8 efficiency operation at full load. NCP4308x 1 The precise turnoff threshold, extremely low turnoff delay time ALYW SOIC8 and high sink current capability of the driver allow the maximum D SUFFIX synchronous rectification MOSFET conduction time. The high CASE 751 1 accuracy driver and 5 V gate clamp make it ideally suited for directly driving GaN devices. Features 1 4308x SelfContained Control of Synchronous Rectifier in CCM, DCM and ALYW DFN8 QR for Flyback or LLC Applications MN SUFFIX CASE 488AF Precise True Secondary Zero Current Detection Rugged Current Sense Pin (up to 150 V) Adjustable Minimum ONTime 1 ExM Adjustable Minimum OFF-Time with Ringing Detection Adjustable Maximum ONTime for CCM Controlling of Primary WDFN8 MT SUFFIX QR Controller CASE 511AT Improved Robust Self Synchronization Capability 8 A / 4 A Peak Current Sink / Source Drive Capability 4308x = Specific Device Code x = A, B, C, D or Q Operating Voltage Range up to V = 35 V CC Ex = Specific Device Code GaN Transistor Driving Capability (options A and C) x = A or D Low Startup Current Consumption A = Assembly Location L = Wafer Lot Maximum Operation Frequency up to 1 MHz Y = Year SOIC-8, DFN8 (4x4) and WDFN8 (2x2) Packages W = Work Week M = Date Code These are PbFree Devices = PbFree Package Typical Applications (Note: Microdot may be in either location) Notebook Adapters High Power Density AC/DC Power Supplies (Cell Phone Chargers) ORDERING INFORMATION LCD TVs See detailed ordering and shipping information on page 26 of All SMPS with High Efficiency Requirements this data sheet. Semiconductor Components Industries, LLC, 2016 1 Publication Order Number: February, 2017 Rev. 1 NCP4308/DNCP4308 RTN D1 OK1 Figure 1. Typical Application Example LLC Converter +Vout Vbulk TR1 R1 C1 C2 C5 D3 VCC M2 D4 FLYBACK C3 CONTROL GND C4 CIRCUITRY DRV M1 FB CS R2 R3 R4 D5 R5 OK1 Figure 2. Typical Application Example DCM, CCM or QR Flyback Converter www.onsemi.com 2 + + MIN TOFF MIN TOFF MIN TON MIN TON +