FD1505 — Synchronous Step-Down MOSFET Driver 1. Overview 1.1. Features High-speed, High-current Drivers for Synchronous NChannel MOSFETs Adaptive Dead-time Control Optimizes Efficiency When Used with Digital-DC™ Controllers Adjustable Gate Drive Voltage: 4.5V to 7.5V Integrated 30V Bootstrap Schottky Diode Capable of Driving ≥ 40A per Phase Supports Switching Frequency up to 1.4MHz >5A Sink Low-side Driver High-side Driver <10ns Rise/Fall Times, Low Propagation Delay Adjustable Gate Drive Strength Optimizes Efficiency for Different VIN, VOUT, IOUT, fSW, and MOSFET Combinations Internal Non-overlap Watchdog Prevents Shootthrough Currents RoHS Compliant, Pb-free Exposed Pad 3 x 3mm DFN-10 Package 1.3. Description The FD1505 is an integrated high-speed, high-current N-channel MOSFET driver for synchronous step-down DC-DC conversion applications. When used with Digital-DC™ PWM controllers, the FD1505 enables dynamically adaptive dead-time control that optimizes efficiency under all operating conditions. A dual input PWM configuration enables this efficiency optimization while minimizing complexity within the driver. Operating from a 4.5V to 7.5V input, the FD1505 combines a 5A, 0.5Ω low-side driver and a 3A, 0.8Ω high-side driver to support high step-down buck applications. A unique adjustable gate drive current scheme allows the user to adjust the drive current on both drivers to optimize performance for a wide range of input/output voltages, load currents, power MOSFETs, and switching frequencies up to 1.4MHz. An integrated 30V bootstrap Schottky diode is used to charge the external bootstrap capacitor. An internal watchdog circuit prevents excessive shoot-through currents and protects the external MOSFET switches. The FD1505 is specified over a wide -40°C to 125°C junction temperature range and is available in an exposed-pad, DFN-10 package. HSEL 1.2. Applications High-Efficiency, High-Current DC-DC Buck Converters with Digital Control and PMBus™ Multi-Phase Digital DC-DC converters with Phase Adding/Dropping Power Train Modules Synchronous Rectification for Secondary Side Isolated Power Converters BST VDD GH PWMH Level shift Shootthrough Protection PWML GL FD1505 GND IMPORTANT NOTE: For additional information, please contact [email protected]. © 2008 Fairchild Semiconductor Corporation FD1505 • Rev. 1.3.1 SW VDD Figure 1. LSEL Block Diagram www.fairchildsemi.com FD1505 — Synchronous Step-Down MOSFET Driver September 2008 FD1505 — Synchronous Step-Dow MOSFET Driver Digital-DC™, and the Zilker Labs Logo are trademarks of Zilker Labs, Inc., used under license by Fairchild Semiconductor. All other products or brand names mentioned herein are trademarks of their respective holders. © 2008 Fairchild Semiconductor Corporation FD1505 • Rev. 1.3.1 www.fairchildsemi.com 14