Description

The PM6641 is a monolithic voltage regulator module specifically designed to supply DDR2/3 memory and chipset in ultra-mobile PC and real estate constrained portable systems.

It integrates three independent, adjustable, constant frequency buck converters, a ±2 Apk low drop-out (LDO) linear regulator and a ±15 mA low noise buffered reference.

Each regulator provides basic UV and OV protections, programmable soft-start and current limit and active soft-end.

Pulse-skipping technique is performed to increase efficiency at very light load.

Features

■ 0.8 V ±1 internal voltage reference

■ 2.7 V to 5.5 V input voltage range

■ Fast response, constant frequency, current mode control

■ Three independent, adjustable, out-of-phase SMPS for DDR2/3 (VDDQ) and chipset supply

■ Low noise DDR2/3 reference (VTTREF)

■ ±2 Apk LDO for DDR2/3 termination (VTT) with foldback

■ S0-S5 states compliant DDR2/3 section

■ Active soft-end for all outputs

■ Selectable tracking discharge for VDDQ

■ Separate Power Good signals

■ Pulse skipping at light load

■ Programmable current limit and soft-start for all outputs

■ Latched OVP, UVP protection

■ Thermal protection

Applications

■ DDR2/3 memory and chipset supply

■ UMPC and portable equipment

■ Handheld and PDAs