FEATURES

VOUT Resistor Programmable Down to 0.9 V

3.3-V or 5.0-V Input Supply

1% DC Accuracy

High Efficiency Synchronous Switching

Drives P-Channel (High Side) and N-Channel

(Low Side) MOSFETs

Lossless Programmable Current Limit

Logic Compatible Shutdown

APPLICATIONS

Local Microprocessor Core Voltage Power

Supplies for Desktop and Notebook

Computers

DSP Core or I/O Powering

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 programmed over a

wide range with a single resistor.