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Monolithic VR for Chipset and DDR2/3 Supply for Ultra-Mobile PC (UMPC) Applications
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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.

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Errata Sheet
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Key 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

Circuit Diagram

Design Resources


Technical Documentation

Product Specifications

Description Version Size
DS5279: Monolithic VR for chipset and DDR2/3 supply for ultra-mobile PC (UMPC) applications
3.0 2,255 KB

Application Notes

Description Version Size
AN2787: Monolithic VR demonstration board for chipset and DDR2/3 supply for ultramobile PC (UMPC) applications
1.0 2,594 KB

Related Tools and Software

Related Tools and Software

Part Number Description
STEVAL-ISA050V1 Monolithic VR for chipset and DDR2/3 demonstration board based on the PM6641 Monolithic VR for Chipset and DDR2/3 Supply for Ultra-Mobile PC (UMPC) applications

Sample & Buy

Part Number Marketing StatusPackagePacking TypeAutomotive GradeOrder From STUnit Price (US$)*
Distributor AvailabilityRoHS Compliance GradeDownload
Material Declaration**
PM6641ActiveVFQFPN 48 7x7x1.0Tray_-No availability reported, please contact our Sales officeEcopack2-
PM6641TRActiveVFQFPN 48 7x7x1.0Tape And Reel_-Distributor reported inventory date: 2016-02-06
Distributor NameRegionStockMin. order
ARROWOrder NowAMERICA24152500

(*) Suggested Resale Price per unit (USD) for BUDGETARY USE ONLY. For quotes, prices in local currency, please contact your local ST Sales Office or our Distributors
(**) The Material Declaration forms available on may be generic documents based on the most commonly used package within a package family. For this reason, they may not be 100% accurate for a specific device. Please contact our sales support for information on specific devices.
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