LM21305 Synchronous Buck Regulator

By Texas Instruments 117

LM21305 Synchronous Buck Regulator

Texas Instruments's LM21305 is a full-featured 5 A synchronous buck regulator optimized for solution size, flexibility, and high conversion efficiency. High power density LM21305 designs are achieved via monolithic integration of the high-side and low-side power MOSFETs, high switching frequency, current-mode control, and optimized thermal design. The efficiency of the LM21305 is elevated at light loads with diode emulation mode operation and at heavy loads by optimal design of the MOSFET gate drivers to minimize switch dead-times and body-diode conduction losses.

  • High efficiency switcher core with integrated low RDSonpower MOSFETs
  • Resistor programmable switching frequency with frequency synchronization
  • Internal soft-start with monotonic and pre-biased startup
  • Low shutdown quiescent current
  • Precision enable with hysteresis
  • PGOOD indicator function
  • Input under-voltage lock-out (UVLO)
  • Output over-voltage protection (OVP)
  • High-bandwidth load transient response with peak current-mode control
  • Cycle-by-cycle current limiting
  • Thermal shutdown


  • POL regulation from 3.3 V, 5 V, and 12 V supply rails
  • High efficiency supply for DSPs, FPGAs, ASICs, and processors
  • Broadband, networking, and optical communications infrastructure

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