FAN5236 Datasheet | onsemi

Features - Highly Flexible, Dual Synchronous Sw itching PWM Controller that Includes Modes for: - DDR Mode w ith In-phase Operation for Reduced Channel Interference - 90° Phase-shifted, Tw o-stage DDR Mode for Reduced Input Ripple - Dual Independent Regulators, 180° Phase Shifted - plete DDR Memory Pow er Solution - VTT Tracks VDDQ/2 - VDDQ/2 Buffered Reference Output - Lossless Current Sensing on Low -side MOSFET or Precision Over-Current Using Sense Resistor - VCC Under-Voltage Lockout - Converters can Operate f rom +5V or 3.3V or Battery Pow er Input (5V to 24V) - Excellent Dynamic Response w ith Voltage Feedforw ard and Average-Current-Mode Control - Pow er-Good Signal - Supports DDR-II and HSTL - Light-Load Hysteretic Mode Maximizes Efficiency - TSSOP28 Package Applications - DDR VDDQ and VTT Voltage Generation - Mobile PC Dual Regulator - Server DDR Pow er i - Hand-held PC Pow er Description The FAN5236 PWM controller provides high ef f iciency and regulation for tw o output voltages adjustable in the range of 0.9V to 5.5V required to pow er I/O, chip-sets, and memory banks in high-performance notebook puters, PDAs, and Internet appliances. Synchronous rectification and hysteretic operation at light loads contribute to high efficiency over a w ide range of loads. The Hysteretic Mode can be disabled separately on each PWM converter if PWM Mode is desired for all load levels. Efficiency is enhanced by using MOSFET RDS(ON) as a current-sense ponent. Feedforw ard ramp modulation, average-current-mode control scheme, and internal feedback pensation provide fast response to load transients. Out-of-phase operation w ith 180-degree phase shift reduces input current ripple. The controller can be transformed into a plete DDR memory pow er supply solution by activating a designated pin. In DDR mode, one of the channels tracks the output voltage of another channel and provides output current sink and source capability - essential for proper pow ering of DDR chips. The...