General Description

The RT6542A PWM controller provides high efficiency,

excellent transient response, and high DC output accuracy

needed for stepping down high voltage batteries to

generate low voltage CPU core, I/O, and chipset RAM

supplies in notebook computers.

The RT6542A supports on chip voltage programming

function between 0.85V and 1.05V by controlling GX digital

inputs.

The constant-on-time PWM control scheme handles wide

input/output voltage ratios with ease and provides 100ns

“instant-on” response to load transients while maintaining

a relatively constant switching frequency.

The RT6542A achieves high efficiency at a reduced cost

by eliminating the current-sense resistor found in

traditional current-mode PWMs. Efficiency is further

enhanced by its ability to drive very large synchronous

rectifier MOSFETs and enter diode emulation mode at

light load condition. The buck conversion allows this device

to directly step down high voltage batteries at the highest

possible efficiency. The RT6542A is intended for CPU core,

chipset, DRAM, or other low voltage supplies as low as

0.7V.

The RT6542A is available in a WDFN-14L 3x2 package.

Features

? Intel Cannon VR Support

? Built-in 1 Reference Voltage

? 2-Bit Programmable Output Voltage with Integrated

Transition Support

? Support Intel LPM (Low-Power Mode) Feature

? 4700ppm/°C Programmable Current Limit by Low-

Side RDS(ON) Sensing

? 3V to 26V Battery Input Range

? Internal Voltage Ramp Soft-Start Control

? Drives Large Synchronous Rectifier FETs

? Integrated Boost Switch

? Over/Under-Voltage Protection

? Thermal Shutdown

? Power Good Indicator

? RoHS Compliant and Halogen Free

? Tiny 14-Lead WDFN Package

Applications

? Notebook Computers

? CPU/GPU Core Supply

? Chipset/RAM Supply

? Generic DC-DC Power Regulator