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