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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > DC DC Switching Controllers

STMicroelectronics L6911DTR

Name: L6911DTR
Brand: STMicroelectronics
SKU: L6911DTR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: L6911DTR

Manufacturer:: STMicroelectronics

Category:: DC DC Switching Controllers

Package:: 20-SOIC (0.295", 7.50mm Width)

Datasheet:: L6911DTR.pdf

Description:: IC REG CTRLR BUCK 20SOIC

Quantity:: RFQ Add To RFQ list

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Product details

Overview

L6911DTR from STMicroelectronics is a 5-bit programmable synchronous buck controller IC designed for high-current microprocessor core power supplies. It delivers voltage-mode PWM control, ±1% output accuracy over line/temperature, 1.3A gate drive capability, and supports output voltages from 1.100V to 1.850V in 25mV binary steps - used in VRM 9.0-compliant CPU power delivery systems.

For engineers reviewing the L6911DTR datasheet, L6911DTR pinout, L6911DTR application, or L6911DTR equivalent, key selection criteria include its TTL-compatible VID interface, R_DS(on)-based overcurrent protection, 200kHz–1MHz adjustable oscillator, soft-start/inhibit functions, and SO-20 package compatibility with high-density PCB layouts.

Technical Context

This controller implements voltage-mode PWM regulation with a 15MHz gain-bandwidth error amplifier and 10V/µs slew rate to enable fast transient response. Its internal 5-bit DAC sets both output voltage (1.100–1.850V @ 25mV steps) and associated PGOOD/OVP thresholds via VID0–VID4 pins.

Protection architecture uses upper MOSFET R_DS(on) sensing for overcurrent detection without external sense resistors, triggers HICCUP-mode recovery on fault, and provides dual overvoltage response: internal low-side MOSFET crowbar activation plus open-drain OVP pin for external SCR triggering.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Voltage Range	1.100V–1.850V in 25mV binary steps per VRM 9.0; programmed via 5-bit VID code
Gate Drive Current	1.3A source/sink on high-side driver; enables fast switching of N-channel MOSFETs with low R_DS(on)
Oscillator Frequency	200kHz internal default; externally adjustable 50kHz–1MHz via RT pin resistor
Output Accuracy	±1% over line and temperature; ensured by trimmed internal reference and DAC
Overcurrent Protection	Realized using upper MOSFET R_DS(on); no external sense resistor required
Soft Start	Programmed via external capacitor on SS pin; 10µA constant-current ramp controls VOUT rise time
Power Good Threshold	Hysteresis: 110–114% (rising), 86–90% (falling); referenced to DAC-set output voltage

Pinout & Package

Package: SO-20 (Small Outline, 20-pin, surface-mount). Pin layout optimized for synchronous buck converter layout with separate PGND and GND, dedicated BOOT and PHASE routing paths, and noise-sensitive analog pins (FB, COMP, VSEN) isolated from power nodes.

Pin/Terminal	Circuit Role	Design Meaning
VSEN	Output voltage monitor input	Direct feedback for PGOOD generation and overvoltage detection; referenced to DAC output
OCSET	Overcurrent threshold setting	200µA current sink sets trip point via external resistor to upper MOS drain
SS/INH	Soft start timing / inhibit control	10µA charging current for external capacitor; <0.4V disables all drivers
VID0–VID4	Digital voltage identification inputs	TTL-compatible pins selecting 1.100–1.850V output in 25mV steps; also set PGOOD/OVP thresholds
COMP	Error amplifier output	Compensation node for voltage loop stability; connects to external RC network
FB	Error amplifier inverting input	Connects to resistor divider from VOUT; forms closed-loop regulation with DAC reference
PGOOD	Open-collector status output	Pulled low when VOUT falls outside ±12% window; requires external pull-up
PHASE	High-side switch source node	Return path for high-side driver; used for R_DS(on) current sensing and bootstrap return
UGATE	High-side MOSFET gate driver	1.3A capable output; driven from BOOT supply to enable N-channel high-side switch
BOOT	Bootstrap capacitor connection	Charged via diode from VCC; supplies UGATE during high-side conduction
LGATE	Low-side MOSFET gate driver	1.1A source/1.3A sink capability; directly powered from VCC
VCC	IC supply input	5V–12V operating range; powers logic, gate drivers, and internal references
OVP	Overvoltage protection output	Open-drain signal to trigger external SCR crowbar at +17% over DAC-set voltage
RT	Oscillator frequency control	Resistor-to-GND increases f_SW; resistor-to-VCC decreases f_SW; floating = 200kHz

Key Features

Feature	Design Value
VRM 9.0 Compliance	5-bit VID interface with 25mV binary steps and coordinated PGOOD/OVP thresholds
R_DS(on)-Based Current Sensing	Eliminates external current-sense resistor; reduces BOM cost and PCB area
Adaptive Dead-Time Control	Prevents shoot-through by delaying high-side turn-on until low-side fully off (≥200ns)
HICCUP-Mode Fault Recovery	Auto-restart after overcurrent/overvoltage clears; no manual reset or power cycle needed
Adjustable Switching Frequency	50kHz–1MHz tuning via single RT resistor enables optimization for efficiency vs. size

Applications

Desktop CPU Core Power Supply

Server Processor VRM Module

Use Scenario: Delivering tightly regulated 1.2V–1.8V at >30A to Intel Pentium III/Xeon processors in ATX motherboards.

IC Role / Device Role / Timing Role: Primary voltage-mode PWM controller managing synchronous buck stage, VID decoding, and real-time load-line compensation.

Use Value: ±1% accuracy and fast transient response (<10µs) maintain CPU VDD within spec during 10A/µs load steps.

Use Scenario: High-density 1U server board requiring multi-phase VRM with individual phase controllers.

IC Role / Device Role / Timing Role: Single-phase controller in multiphase configuration; coordinates with other L6911DTR units via shared VID bus and synchronized RT networks.

Use Value: Adjustable 200kHz–1MHz f_SW allows phase interleaving to reduce input/output ripple and EMI.

Embedded x86 Processor Power

Industrial FPGA Core Supply

Use Scenario: Powering VIA C3 or AMD Geode processors in fanless industrial PCs with wide ambient temperature range.

IC Role / Device Role / Timing Role: Standalone buck controller providing stable core voltage under variable thermal and load conditions.

Use Value: ±1% accuracy over 0–125°C junction temperature ensures reliable operation without derating.

Use Scenario: Supplying 1.2V core voltage to Xilinx Virtex-II Pro FPGAs in programmable logic controllers.

IC Role / Device Role / Timing Role: Precision voltage regulator with programmable soft-start to prevent inrush current during FPGA configuration.

Use Value: SS/INH pin enables controlled power sequencing with system management controller.

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous buck controller applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
ISL6522CRZ	6-bit VID resolution (10mV steps), integrated MOSFET drivers with 3A peak current, fixed 300kHz oscillator	Targets higher-precision VRM 10.x designs; lacks RT-adjustable frequency	Select for tighter voltage tolerance requirements where 10mV step resolution is mandatory
TPS51116PWR	Integrated 5V LDO for VCC bias, dual MOSFET drivers, 500kHz fixed frequency, no external OCSET resistor	Designed for notebook CPU VRMs with embedded 5V rail; less flexible for discrete power stages	Select when board space is constrained and 5V auxiliary supply integration is beneficial

Compared with ISL6522CRZ and TPS51116PWR, the L6911DTR offers wider frequency adjustability (50kHz–1MHz), lower gate drive current (1.3A vs. 3A/1.5A), and explicit R_DS(on)-based current sensing - making it optimal for cost-sensitive, thermally demanding desktop/server VRM implementations where design flexibility outweighs ultra-fine voltage granularity.

Availability

L6911DTR is available at Aetrix Electronics and suitable for desktop motherboard power delivery, server VRM modules, embedded x86 processor supplies, and industrial FPGA core regulators requiring stable component supply across extended product lifecycles.

Supply support for L6911DTR 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 headquartered in Geneva, Switzerland, specializing in power management, microcontrollers, and analog ICs for industrial, automotive, and computing markets.

The L6911DTR belongs to ST's VRM-compliant synchronous buck controller product line, engineered specifically for high-efficiency, high-transient-response core power delivery to advanced microprocessors in desktop, server, and embedded platforms.

FAQ

What is the minimum recommended output capacitance for L6911DTR in a 1.2V/30A application?

The minimum output capacitance depends on load transient magnitude and allowable voltage droop. For a 10A/µs step with ≤50mV droop, ≥1000µF low-ESR polymer or MLCC+polymer hybrid is typical. ST Application Note AN2027 specifies 1500µF total with ESR ≤1.5mΩ for 1.2V/30A VRM 9.0 compliance, including ESL mitigation via parallel small-case MLCCs near the CPU socket.

Can L6911DTR operate with an input voltage below 5V?

No. The absolute minimum VCC supply is 4.6V (turn-on threshold), and the recommended operating range is strictly 5V to 12V. Input voltages below 5V risk unreliable startup, degraded gate drive strength, and loss of VID decoding accuracy. For sub-5V input applications, a dedicated bias supply or upstream DC-DC pre-regulator is required.

How does the L6911DTR implement overvoltage protection without external components?

L6911DTR provides dual overvoltage protection: internally, it turns on the low-side MOSFET continuously to short the output when VSEN exceeds +17% of DAC-set voltage; externally, it drives the OVP pin high to trigger an SCR crowbar circuit. Both actions occur simultaneously upon detection - no external comparator or timer is needed for basic protection.

Is the L6911DTR pin-compatible with newer ST controllers like the L6920DB?

No. L6920DB is a monolithic synchronous buck converter (integrated MOSFETs, different pin count and function mapping), while L6911DTR is a controller-only SO-20 device with distinct VID, OCSET, BOOT, and PHASE pin assignments. Direct replacement requires full schematic and layout redesign due to incompatible topology, gate drive architecture, and protection signaling.

L6911DTR Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: 20-SOIC (0.295", 7.50mm Width)

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Output Type:: Transistor Driver

Function:: Step-Down

Output Configuration:: Positive

Topology:: Buck

Number of Outputs:: 1

Output Phases:: 1

Voltage - Supply (Vcc/Vdd):: 5V ~ 12V

Frequency - Switching:: 200kHz

Duty Cycle (Max):: 100%

Synchronous Rectifier:: Yes

Clock Sync:: No

Serial Interfaces:: -

Control Features:: Current Limit, Frequency Control, Phase Control, Power Good, Soft Start

Operating Temperature:: 0°C ~ 125°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 20-SO

L6911DTR FAQ

1.How can I place an order for L6911DTR through Aetrix?

Please submit a Request for Quotation (RFQ) for L6911DTR 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 L6911DTR reliable?

The price and inventory of L6911DTR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L6911DTR is usually 5 days.

3.What payment methods are accepted for L6911DTR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L6911DTR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for L6911DTR?

L6911DTR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your L6911DTR 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 L6911DTR?

For technical support, including L6911DTR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L6911DTR requirements.

6.How does Aetrix verify that L6911DTR is sourced from the original manufacturer or authorized distributors?

All L6911DTR 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 L6911DTR meets industry standards.

7.What is the process for return or replacement of L6911DTR?

All L6911DTR units undergo pre-shipment inspection (PSI). If there is an issue with L6911DTR, 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 L6911DTR part is unused and in its original packaging.

Return procedure for L6911DTR:

1.Submit a request within 90 days.

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

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