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

STMicroelectronics L6917BD

Name: L6917BD
Brand: STMicroelectronics
SKU: L6917BD
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: L6917BD

Manufacturer:: STMicroelectronics

Category:: DC DC Switching Controllers

Package:: 28-SOIC (0.295", 7.50mm Width)

Datasheet:: L6917BD.pdf

Description:: IC REG CTRLR BUCK 28SO

Quantity:: RFQ Add To RFQ list

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Inventory:1,485

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Product details

Overview

L6917BD from STMicroelectronics is a dual-phase synchronous buck controller IC designed for high-current microprocessor power supplies. It delivers 5-bit VID-programmable output voltage (1.100–1.850 V in 25 mV steps), ±0.8% internal reference accuracy, and 300 kHz to 600 kHz adjustable switching frequency with integrated 2 A gate drivers per phase. Used in server VRMs with remote sensing and active current sharing.

For engineers reviewing the L6917BD datasheet, L6917BD pinout, L6917BD application, or L6917BD equivalent, key selection criteria include dual-phase adaptive current sharing (±10%), TTL-compatible VID interface, programmable soft-start (2048-step digital ramp), overvoltage crowbar protection, and SO-28 package compatibility with high-noise DC-DC converter layouts.

Technical Context

The L6917BD implements average current-mode control with 180° phase interleaving to reduce input ripple and improve transient response. Its error amplifier features 15 V/µs slew rate and 80 dB DC gain, enabling fast load step recovery without external compensation instability.

Current sensing uses fully differential architecture across either MOSFET R_DS(on) or external sense resistors, with dedicated PGNDSx pins and noise-coupled routing guidance. Protection logic includes latched UVP/OVP, constant-current mode during overcurrent, and adaptive anti-cross-conduction timing with 30 ns dead-time control.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Voltage Range	1.100 V to 1.850 V in 25 mV binary steps via 5-bit VID inputs
Reference Accuracy	±0.8% over temperature and line variation - ensures tight regulation without external trimming
Switching Frequency	300 kHz (internal) to 600 kHz (externally adjustable via ROSC) - balances efficiency vs. size in VRM designs
Gate Drive Current	Up to 2 A source/sink per driver - supports fast switching of low-R_DS(on) N-channel MOSFETs
Current Sharing Accuracy	±10% across both phases under static and dynamic load - enables balanced thermal distribution
Soft-Start Resolution	Digital 2048-step ramp - eliminates output overshoot during power-up in sensitive CPU rails
OVP/UVP Response	Crowbar activation on OVP; latched shutdown on UVP - protects microprocessor from rail faults

Pinout & Package

Package: SO-28 (Small Outline, 28-pin, 300 mil width, standard JEDEC MS-013AC).

Pin	Circuit Role	Design Meaning
1, 27	LGATE1 / LGATE2	Low-side gate driver outputs - drive N-MOS sources directly; sink/source up to 1.8 A
4, 25	UGATE1 / UGATE2	High-side gate driver outputs - bootstrap-supplied; deliver up to 2 A peak into MOS gate capacitance
3, 26	PHASE1 / PHASE2	High-side return paths - connect to upper MOS source; critical for bootstrap capacitor biasing
5, 24	BOOT1 / BOOT2	Bootstrap supply pins - connect to PHASEx via capacitor and VCC via diode; enable floating high-side drive
13, 16	ISEN1 / ISEN2	Differential current sense inputs - read voltage drop across R_DS(on) or sense resistor with common-mode noise rejection
14, 15, 28	PGNDS1 / PGNDS2 / PGND	Power ground sense and return - separate low-impedance paths minimize sensing error and EMI coupling
18–22	VID4–VID0	TTL-compatible digital inputs - program output voltage, PGOOD thresholds, and OVP trip points per Table 1
17	OSC/INH/FAULT	Multi-function pin - sets oscillator frequency, enables inhibit mode (<0.8 V), and latches fault status

Key Features

Feature	Design Value
Dual-phase interleaved control	180° phase shift reduces input capacitor RMS current by ~30%, lowering required capacitance and ESR
Remote sensing buffer	Integrated differential amplifier (FBR/FBG) rejects PCB trace IR drop - maintains ±0.5% regulation at load
Adaptive anti-cross-conduction	Dynamic dead-time control (30 ns fixed + watchdog) prevents shoot-through while minimizing body diode conduction
Programmable droop compensation	FB pin sourcing 50 µA at full load enables precise current-sharing droop without external op-amps
Open-drain PGOOD output	Asserts after soft-start completion when VSEN is within 84–116% of DAC-set voltage - synchronizes system power sequencing

Applications

Server VRM Power Stage

Workstation CPU Core Rail

Use Scenario: Dual-phase 12 V input to 1.3 V/150 A output for dual-socket Xeon platforms with dynamic load steps >50 A/µs.

IC Role / Device Role / Timing Role: Primary voltage regulation controller managing phase interleaving, current balancing, and fast transient correction via error amplifier bandwidth.

Use Value: ±10% current sharing accuracy prevents thermal imbalance between parallel MOSFET banks; 2048-step soft-start avoids CPU reset during cold boot.

Use Scenario: High-efficiency core supply for AMD Threadripper workstations requiring tight voltage tolerance (±3%) under burst loads.

IC Role / Device Role / Timing Role: Synchronous buck controller with remote sense buffer compensating for 50 mΩ PCB trace resistance between regulator and CPU socket.

Use Value: Integrated 0.8% reference and differential VSEN/FBR/FBG path maintain regulation accuracy despite board-level IR drop.

Distributed DC-DC Module

High-Current FPGA Supply

Use Scenario: Compact 25 mm × 25 mm module delivering 1.2 V/80 A to ASIC clusters in telecom baseband units.

IC Role / Device Role / Timing Role: Dual-phase controller with externally adjustable 450 kHz switching - optimizes magnetics size vs. efficiency trade-off.

Use Value: ROSC-adjustable frequency allows tuning for lowest total loss with specific MOSFETs and inductors; SO-28 footprint simplifies layout density.

Use Scenario: Reconfigurable 1.0 V rail for Xilinx Versal ACAP with dynamic voltage scaling and rapid load transients up to 40 A/µs.

IC Role / Device Role / Timing Role: VID-programmable controller supporting real-time voltage adjustment via FPGA GPIOs tied to VID0–VID4.

Use Value: TTL-compatible VID inputs enable direct FPGA control; 15 V/µs error amp slew rate sustains regulation during 100 ns load steps.

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-phase VRM controller applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
ISL6522CRZ	Fixed 300 kHz oscillator; no ROSC adjustability; 1.5 A gate drive; requires external current-sense amplifiers	Lacks integrated remote sense buffer and digital soft-start - needs more external components for same functionality	Prefer where cost-sensitive designs accept reduced integration and tighter frequency tolerance
TPS546B24A	PMBus-compliant digital controller; 0.5% reference; supports 3+ phases; integrated MOSFET drivers not included	Requires external gate drivers and power stages; adds telemetry but increases BOM count and firmware dependency	Choose when telemetry, margining, and multi-phase scalability outweigh analog simplicity and SO-28 footprint

Compared with ISL6522CRZ and TPS546B24A, the L6917BD offers superior analog integration (gate drivers, remote sense, droop compensation) in a compact SO-28 package, making it optimal for space-constrained, high-reliability VRMs where digital complexity and external component count must be minimized.

Availability

L6917BD is available at Aetrix Electronics and suitable for server VRMs, workstation CPU power supplies, and distributed DC-DC converters requiring stable component supply, long-lifecycle support, and proven field reliability in high-temperature environments.

Supply support for L6917BD 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, specializing in power management, microcontrollers, and analog ICs for industrial, automotive, and computing markets.

The L6917BD belongs to ST's high-performance VRM controller product line, engineered specifically for Intel/AMD-compliant microprocessor power delivery with emphasis on transient response, current sharing, and robust protection in multi-phase buck topologies.

FAQ

What is the maximum supported switching frequency and how is it adjusted?

The L6917BD supports up to 600 kHz switching frequency. It is adjusted using an external resistor (ROSC) connected from the OSC/INH/FAULT pin to GND (increases frequency) or to VCC (decreases frequency). With ROSC = 0 Ω to GND, frequency reaches ~550 kHz; with ROSC = 74 kΩ to GND, it achieves ~500 kHz. The internal default is 300 kHz when OSC is left open.

How does the L6917BD implement current sharing between phases?

It uses fully differential current sensing on ISEN1/PGNDS1 and ISEN2/PGNDS2 pins to measure per-phase current, then applies PWM correction to equalize average current. This achieves ±10% matching across static and dynamic conditions without external op-amps or discrete current mirrors, leveraging internal transconductance and matched circuitry.

Can the L6917BD operate with only one phase enabled?

No - the L6917BD is strictly a dual-phase controller with fixed 180° interleaving. Both phases are always active and synchronized; there is no provision for single-phase operation or phase shedding. Disabling one channel is not supported and will cause regulation failure or protection activation.

What happens during an overvoltage event and how is recovery performed?

On overvoltage detection at VSEN, the device immediately activates a crowbar by turning ON the low-side MOSFETs to clamp the output, pulls FAULT high, and disables all gate drivers. Recovery requires cycling both VCC and VCCDR supplies - the latch cannot be reset by toggling INH alone or via software.

L6917BD Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: 28-SOIC (0.295", 7.50mm Width)

Packaging:: Tube

Product Status:: Obsolete

Output Type:: Transistor Driver

Function:: Step-Down

Output Configuration:: Positive

Topology:: Buck

Number of Outputs:: 2

Output Phases:: 2

Voltage - Supply (Vcc/Vdd):: 7.5V ~ 15V

Frequency - Switching:: 300kHz

Duty Cycle (Max):: 75%

Synchronous Rectifier:: Yes

Clock Sync:: No

Serial Interfaces:: -

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

Operating Temperature:: -25°C ~ 125°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 28-SO

L6917BD FAQ

1.How can I place an order for L6917BD through Aetrix?

Please submit a Request for Quotation (RFQ) for L6917BD 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 L6917BD reliable?

The price and inventory of L6917BD are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L6917BD is usually 5 days.

3.What payment methods are accepted for L6917BD?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L6917BD transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for L6917BD?

L6917BD orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your L6917BD 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 L6917BD?

For technical support, including L6917BD datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L6917BD requirements.

6.How does Aetrix verify that L6917BD is sourced from the original manufacturer or authorized distributors?

All L6917BD 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 L6917BD meets industry standards.

7.What is the process for return or replacement of L6917BD?

All L6917BD units undergo pre-shipment inspection (PSI). If there is an issue with L6917BD, 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 L6917BD part is unused and in its original packaging.

Return procedure for L6917BD:

1.Submit a request within 90 days.

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

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