General Description

The MAX1715 PWM controller provides the 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.

Maxim’s proprietary Quick-PWM™ quick-response,

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 MAX1715 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 synchronousrectifier MOSFETs.

Single-stage buck conversion allows this device to

directly step down high-voltage batteries for the highest

possible efficiency. Alternatively, two-stage conversion

(stepping down the +5V system supply instead of the

battery) at a higher switching frequency allows the minimum possible physical size.

The MAX1715 is intended for CPU core, chipset,

DRAM, or other low-voltage supplies as low as 1V. The

MAX1715 is available in a 28-pin QSOP package. For

applications requiring VID compliance or DAC control

of output voltage, refer to the MAX1710/MAX1711 data

sheet. For a single-output version, refer to the MAX1714

data sheet.

Features

♦ Ultra-High Efficiency

♦ No Current-Sense Resistor (lossless ILIMIT)

♦ Quick-PWM with 100ns Load-Step Response

♦ 1% VOUT Accuracy over Line and Load

♦ Dual-Mode Fixed 1.8V/3.3V/Adj or 2.5V/Adj Outputs

♦ Adjustable 1V to 5.5V Output Range

♦ 2V to 28V Battery Input Range

♦ 200/300/420/540kHz Nominal Switching Frequency

♦ Over/Undervoltage Protection

♦ 1.7ms Digital Soft-Start

♦ Drives Large Synchronous-Rectifier FETs

♦ Power-Good Indicator