UCC2585

UCC3585 Not Recommended for New Designs UCC2585 UCC3585 SLUS304F − JULY 1999 − REVISED JANUARY 2005 LOWĆVOLTAGE SYNCHRONOUS BUCK CONTROLLER FEATURES D VOUT Resistor Programmable Down to 0.9 V D 3.3-V or 5.0-V Input Supply D 1% DC Accuracy D High Efficiency Synchronous Switching D Drives P-Channel (High Side) and N-Channel (Low Side) MOSFETs D Lossless Programmable Current Limit D Logic Compatible Shutdown APPLICATIONS D Local Microprocessor Core Voltage Power Supplies for Desktop and Notebook Computers D DSP Core or I/O Powering D High-Speed GTL Bus Regulation DESCRIPTION The UCC3585 synchronous buck controller provides flexible high efficiency power conversion for output voltages as low as 0.9 V with ensured ±1% dc accuracy. With an input voltage range of 3.0 V to 5.5 V, it is the ideal choice for 3.3 V only, 5.0 V only, or other low voltage systems. The fixed frequency oscillator is capable of providing practical PWM operation to 500 kHz. The UCC3585 drives a complementary pair of power MOSFET transistors. A P-channel on the high side, and an N-channel on the low side step down the input voltage at up to 90% efficiency. A programmable two-level current limiting function is provided by sensing the voltage drop across the high side P-channel MOSFET. This circuit can be configured to provide pulseby-pulse limiting, timed shutdown after seven consecutive faults, or latch-off after fault detection, allowing maximum application flexibility. The current limit threshold can be ...