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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Power Management - Specialized

STMicroelectronics PM6670STR

Name: PM6670STR
Brand: STMicroelectronics
SKU: PM6670STR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: PM6670STR

Manufacturer:: STMicroelectronics

Category:: Power Management - Specialized

Package:: 24-VFQFN Exposed Pad

Datasheet:: PM6670STR.pdf

Description:: IC CTLR DDR2/3 MEM PS 24VFQFPN

Quantity:: RFQ Add To RFQ list

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Product details

Overview

PM6670STR from STMicroelectronics is a complete DDR2/3 memory power supply controller integrating a constant-on-time (COT) buck controller for VDDQ, a 2 A sink/source LDO for VTT, and a ±15 mA low-noise buffered VTTREF. It delivers fixed 1.8 V (DDR2) or 1.5 V (DDR3) VDDQ outputs with ±1% accuracy, supports ceramic output capacitors, and enables S3/S4/S5 sleep-state compliance. It is used in notebook computers and handheld devices requiring JEDEC-compliant DDR termination and fast transient response.

For engineers reviewing the PM6670STR datasheet, PM6670STR pinout, PM6670STR application, or PM6670STR equivalent, key selection criteria include its dual-mode VDDQ output configuration (fixed vs. adjustable), integrated VTT/VTTREF tracking architecture, no-RSENSE current sensing via MOSFET R_DS(ON), negative current limit capability, and S3/S5-controlled high-Z VTT state during suspend-to-RAM.

Technical Context

The PM6670STR implements a constant-on-time (COT) PWM control loop for the VDDQ buck section, enabling ultra-fast load transient response without external compensation. Its embedded integrator compensates DC voltage error caused by output ripple, supporting both electrolytic and ceramic capacitors while maintaining stability across input voltages from 4.5 V to 28 V.

The VTT LDO operates as a 2 A sink/source linear regulator with foldback current limiting and remote sensing (VTTSNS), while the VTTREF buffer provides a ±15 mA, low-noise 0.9 V reference derived from VSNS/2. The device fully complies with JEDEC DDR2/3 termination requirements and supports system-level power states via dedicated S3 and S5 pins that control VTT high-impedance mode and coordinated discharge sequencing.

Key Specifications

Parameter	Value and Actual Design Meaning
VDDQ Output Voltage	Fixed 1.8 V (DDR2) or 1.5 V (DDR3); ±1% accuracy ensures SSTL18/HSTL/SSTL15 bus termination compliance.
VDDQ Input Range	4.5 V to 28 V; supports wide-input industrial and notebook DC-DC front-end supplies.
VTT LDO Current	±2 A sink/source; enables full DDR2/3 bidirectional termination current handling without external components.
VTTREF Accuracy	±2% vs. VSNS/2; guarantees precise tracking of VDDQ/2 for accurate DDR termination reference.
Switching Frequency	Adjustable via VOSC pin (150–500 kHz); allows optimization of efficiency, size, and audible noise.
Soft-Start Time	Internally fixed at 3 ms; prevents inrush current and ensures controlled power-up of DDR memory rails.
Thermal Shutdown	150 °C junction temperature; protects against thermal runaway during overload or poor PCB heatsinking.

Pinout & Package

The PM6670STR is housed in a VFQFPN-24 4×4 mm package with exposed thermal pad, optimized for high-power density DDR memory regulation and thermal dissipation in space-constrained applications.

Pin/Terminal	Circuit Role	Design Meaning
VTTGND	LDO power ground	Must connect to negative terminal of VTT output capacitor and shared low-impedance ground plane with SGND and thermal pad.
VTTSNS	VTT remote sense input	Enables precision regulation at DDR load point; requires short, low-noise PCB trace to memory module.
DDRSEL	DDR voltage mode selector	Configures VDDQ output: tied to AVCC for DDR2 (1.8 V), grounded for DDR3 (1.5 V) in fixed mode.
VTTREF	Buffered DDR reference output	Provides stable 0.9 V (DDR2) or 0.75 V (DDR3) reference; requires ≥22 nF ceramic bypass for stability.
VSNS	VDDQ remote sense input	Enables accurate VDDQ regulation at memory load; also feeds internal divider for VTTREF generation.
MODE	Operation mode selector	Voltage >4 V selects fixed-output mode; <4 V enables adjustable mode using external feedback resistors.
COMP	Error amplifier compensation node	External RC network sets loop bandwidth and phase margin for COT buck stability.
DSCG	Discharge mode control	Selects tracking/non-tracking discharge behavior for VDDQ, VTT, and VTTREF during power-down.
S3	Suspend-to-RAM enable	Pulls VTT to high-Z state when asserted low; required for S3 power state compliance.
S5	Suspend-to-disk enable	Triggers full discharge sequence for all outputs when asserted low; required for S4/S5 compliance.
PG	Power Good open-drain output	Asserts high when VDDQ is within ±10% of nominal; used for system power sequencing and fault detection.
CSNS	Current sense input	Connects to synchronous rectifier drain to set current limit threshold using MOSFET R_DS(ON).
LGATE / HGATE	Gate driver outputs	Drive external N-channel MOSFETs; LGATE pull-down resistance ≤0.9 Ω, HGATE pull-down ≤2.7 Ω.
PHASE	Switch node connection	Return path for HGATE driver; must be routed with minimal inductance to reduce switching losses.
BOOT	Bootstrap supply input	Charges high-side gate driver bootstrap capacitor; requires 100 nF ceramic capacitor to PHASE.
LDOIN	VTT LDO input	Typically connected to VDDQ rail; can be supplied from lower voltage to reduce LDO power dissipation.
VTT	VTT LDO output	Delivers ±2 A with remote sensing; bypassed with 20 μF (2×10 μF MLCC) ceramic capacitor.

Key Features

Feature	Design Value
No-RSENSE current sensing	Uses low-side MOSFET R_DS(ON) instead of discrete sense resistor - reduces BOM cost and PCB area.
Negative current limit	Detects reverse current flow during light-load or transient conditions - prevents VDDQ rail collapse during DDR bus turnaround.
Ceramic capacitor support	Stable operation with MLCCs on VDDQ, VTT, and VTTREF outputs - eliminates bulk electrolytics and improves reliability.
Three pulse-skip modes	Selectable forced PWM, pulse-skip, and no-audible (33 kHz) pulse-skip - balances efficiency, EMI, and acoustic noise.
S3/S5 power management	Dedicated pins enable JEDEC-compliant suspend-to-RAM (high-Z VTT) and suspend-to-disk (coordinated discharge) behavior.

Applications

DDR2 Memory Power Supply

DDR3 Memory Power Supply

Use Scenario: Providing regulated 1.8 V VDDQ and 0.9 V VTT for DDR2 SDRAM modules in ultraportable notebooks.

IC Role / Device Role / Timing Role: Dual-rail controller delivering JEDEC-compliant DDR2 termination and core supply with synchronized soft-start and discharge.

Use Value: Eliminates need for separate VDDQ controller and VTT LDO, reducing component count by ≥4 ICs and simplifying layout.

Use Scenario: Generating 1.5 V VDDQ and 0.75 V VTT for DDR3 SO-DIMMs in industrial embedded systems operating from 12 V input.

IC Role / Device Role / Timing Role: Integrated power management unit ensuring DDR3 bus integrity during dynamic read/write bursts and deep-sleep transitions.

Use Value: Achieves <100 ns VTT transient response to ±2 A load steps - maintains signal integrity on high-speed DDR3 buses up to 1066 MT/s.

Notebook Computer Power Architecture

CPU Chipset I/O Supply

Use Scenario: Consolidating DDR memory rail regulation in thin-and-light laptop platforms where board space and thermal headroom are constrained.

IC Role / Device Role / Timing Role: Single-chip solution managing VDDQ, VTT, and VTTREF with shared thermal design and unified sequencing logic.

Use Value: Reduces total solution footprint by 35% versus discrete controllers + LDOs, while enabling fanless thermal design up to 85 °C ambient.

Use Scenario: Delivering SSTL15-compliant termination for CPU chipset I/O interfaces in server motherboard reference designs.

IC Role / Device Role / Timing Role: Precision reference generator (VTTREF) and low-noise LDO (VTT) ensuring sub-25 mV VTT accuracy under ±1 A dynamic loads.

Use Value: Maintains <±20 mV VTT output accuracy across -40 °C to +85 °C - meets JEDEC JESD8-12A SSTL15 specification.

Equivalent & Alternatives

The following parts are listed as comparable options for similar DDR memory power supply applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
TPS51220RGER	Single-channel VDDQ controller only; lacks integrated VTT LDO and VTTREF buffer - requires two additional ICs for full DDR2/3 support.	Requires external 2 A VTT LDO and reference buffer; increases BOM count, layout complexity, and power sequencing overhead.	Choose when only VDDQ regulation is needed or when VTT is generated separately for thermal partitioning.
ISL6537CRZ	Legacy dual-rail DDR2 controller with fixed 1.8 V VDDQ and 0.9 V VTT; no DDR3 mode, no VTTREF buffer, and no S3/S5 sleep-state support.	Not compliant with DDR3 JEDEC specs or modern OS power states; limited to legacy DDR2-only designs.	Only suitable for cost-sensitive DDR2-only upgrades where S3/S5 compliance is not required.

Compared with TPS51220RGER and ISL6537CRZ, the PM6670STR uniquely integrates full DDR2/3 dual-rail regulation, VTTREF buffering, and JEDEC-compliant S3/S5 power management in one VFQFPN-24 package - reducing system-level component count by up to 3 ICs and eliminating external sequencing logic.

Availability

PM6670STR is available at Aetrix Electronics and suitable for notebook computers, DDR2/3 memory modules, and CPU chipset I/O supplies requiring stable component supply, long-term lifecycle support, and JEDEC-compliant power sequencing.

Supply support for PM6670STR includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader specializing in power management, microcontrollers, and analog ICs, with broad manufacturing scale and automotive-grade quality systems.

The PM6670STR belongs to ST's DDR memory power controller product line, designed specifically to replace multi-IC DDR2/3 power solutions with single-chip integration targeting space-constrained, thermally sensitive computing platforms.

FAQ

What is the recommended output capacitor configuration for VDDQ when using ceramic capacitors?

Use ≥47 μF total ceramic capacitance (e.g., four 10 μF X5R 0805 MLCCs) placed close to the PM6670STR's VSNS and PGND pins. The COT control loop is optimized for ceramic output caps; no bulk electrolytic is required. Ensure low-ESR layout with short, wide traces to minimize impedance and maintain stability under fast transients.

How does the PM6670STR achieve VTT/VTTREF tracking to VDDQ/2?

The PM6670STR internally divides the VSNS voltage by two and uses it as the reference for both VTTREF buffer and VTT LDO error amplifiers. VTTSNS and VSNS must be routed as matched-length, low-noise differential pairs to preserve tracking accuracy. This architecture ensures VTT remains within ±20 mV of VDDQ/2 across load and temperature - meeting JEDEC DDR2/3 termination tolerance.

Can the PM6670STR operate in DDR2 and DDR3 modes simultaneously?

No. DDRSEL pin configures the device for either DDR2 (1.8 V VDDQ / 0.9 V VTT) or DDR3 (1.5 V VDDQ / 0.75 V VTT) operation - it cannot generate both voltages concurrently. The MODE pin further selects fixed-output or adjustable mode, but the DDRSEL setting determines the JEDEC standard compliance target and internal reference scaling.

What happens to VTT during S3 (suspend-to-RAM) state?

When the S3 pin is driven low, the VTT LDO enters high-impedance state - disconnecting the output from LDOIN and preventing current flow into or out of the DDR bus. This preserves memory contents during suspend while eliminating VTT-related standby power loss. VTT resumes regulation immediately upon S3 deassertion, with no re-start delay.

PM6670STR Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: 24-VFQFN Exposed Pad

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Applications:: Memory, DDR2/DDR3 Regulator

Current - Supply:: 800µA

Voltage - Supply:: 4.5V ~ 28V

Operating Temperature:: -40°C ~ 85°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 24-VFQFPN (4x4)

PM6670STR FAQ

1.How can I place an order for PM6670STR through Aetrix?

Please submit a Request for Quotation (RFQ) for PM6670STR on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for PM6670STR reliable?

The price and inventory of PM6670STR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for PM6670STR is usually 5 days.

3.What payment methods are accepted for PM6670STR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for PM6670STR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for PM6670STR?

PM6670STR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your PM6670STR order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for PM6670STR?

For technical support, including PM6670STR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your PM6670STR requirements.

6.How does Aetrix verify that PM6670STR is sourced from the original manufacturer or authorized distributors?

All PM6670STR products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that PM6670STR meets industry standards.

7.What is the process for return or replacement of PM6670STR?

All PM6670STR units undergo pre-shipment inspection (PSI). If there is an issue with PM6670STR, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The PM6670STR part is unused and in its original packaging.

Return procedure for PM6670STR:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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