Part # LM2657 datasheet

Part Manufacturer: National Semiconductor

National Semiconductor

Part Description: LM2657 Dual Synchronous Buck Regulator Controller

Part Details:

LM2657 March 2005 Dual LM2657Dual Synchronous Buck Regulator Controller Synchronous General Description Features The LM2657 is an adjustable 200kHz-500kHz dual channel n Input voltage range from 4.5V to 28V voltage-mode controlled high-speed synchronous buck n Synchronous dual-channel interleaved switching regulator controller ideally suited for high current applica- n Forced-PWM or Pulse-skip modes tions. The LM2657 requires only N-channel FETs for both n Lossless bottom-side FET current sensing the upper and lower positions of each stage. It features line n Adaptive duty cycle clamp feedforward to improve the response to input transients. At n High current N-channel FET drivers very light loads, the user can choose between the high-efficiency Pulse-skip mode or the constant frequency n Low shutdown supply current Buck Forced-PWM mode. Lossless current limiting without the use n Reference voltage accurate to within ±1.5% of external sense resistors is made possible by sensing the n Output voltage adjustable down to 0.6V voltage drop across the bottom FET. A unique adaptive duty n Power Good flag and Chip Enable cycle clamping technique is incorporated to significantly re- Regulator n Under-voltage lockout duce peak currents under abnormal load conditions. The two n Over-voltage/Under-voltage protection independently programmable outputs switch 180° out of n Soft-start phase (interleaved switching) reducing the input capacitor n Switching frequency adjustable 200kHz-500kHz and filter requirements. The input voltage range is 4.5V to n TSSOP-28 package 28V while the output voltages are adjustable down to 0.6V. Standard supervisory and control features include Soft-start, Applications Power Good, output Under-voltage and Over-voltage protec- Controller tion, Under-voltage Lockout, and chip Enable. n Low Output Voltage High-Efficiency Buck Regulators Typical Application (Channel 2 in parenthesis) 20134704 © 2005 National Semiconductor Corporation DS201347 Typical Application (Channel 2 in parenthesis) (Continued) LM2657 Connection Diagram

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LM2657.pdf Datasheet