Send an Inquiry

To receive a quote for your project, please fill in the following information, and we’ll get back to you promptly.

Submit Inventory List

Please fill in the following information, and we’ll get back to you promptly.

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

Analog Devices Inc. LTC3811EUHF#PBF

Name: LTC3811EUHF#PBF
Brand: Analog Devices Inc.
SKU: LTC3811EUHF#PBF
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: LTC3811EUHF#PBF

Manufacturer:: Analog Devices Inc.

Category:: DC DC Switching Controllers

Package:: 38-WFQFN Exposed Pad

Datasheet:: LTC3811EUHF#PBF.pdf

Description:: IC REG CTRLR BUCK 38QFN

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:4,907

Please send an inquiry. Send us your inquiry, and we will respond immediately.

Product details

Overview

LTC3811EUHF#PBF from Analog Devices (formerly Linear Technology) is a dual-output, multiphase synchronous step-down DC/DC controller optimized for low-voltage, high-current applications up to 3.3V output. It supports 1–12-phase operation via MODE/SYNC, CLKOUT, and PHASEMODE pins; features ±0.5% output voltage accuracy over temperature; programmable current sense threshold (24–85 mV); and operates from 4.5V to 30V input with 250–750 kHz adjustable switching frequency. Used in network server core/I/O power supplies.

For engineers reviewing the LTC3811EUHF#PBF datasheet, LTC3811EUHF#PBF pinout, LTC3811EUHF#PBF application, or LTC3811EUHF#PBF equivalent, key selection criteria include its dual-channel PolyPhase® architecture, differential remote sensing capability, DCR or resistor-based current sensing, voltage positioning (QFN only), and thermal shutdown at 165°C - all critical for high-density, low-V_OUT power delivery systems.

Technical Context

The LTC3811EUHF#PBF implements fixed-frequency peak current mode control with two independent error amplifiers (8 MHz unity-gain bandwidth, ±0.5% V_FB accuracy), a high-speed differential remote sense amplifier (1.000 V/V gain, ±6 mV offset), and programmable phase relationships via PHASEMODE pin (0°/120°/180° between channels). Its internal 6 V / 100 mA DRVCC LDO powers bottom gate drivers, while EXTVCC support enables external high-current gate drive bypassing the LDO.

Multiphase synchronization uses an integrated PLL with 175–900 kHz sync range and configurable oscillator frequency (250–750 kHz via PLL/LPF pin). The device supports selectable CCM/DCM operation, soft-start/tracking via SS/TRACK pins, and voltage positioning (gm = 5.0 mS, CSOUT pin) exclusively in the QFN package - enabling precise load-line droop programming for CPU/GPU VRMs.

Key Specifications

Parameter	Value and Actual Design Meaning
Topology	Dual-output, synchronous buck controller with PolyPhase® multiphase support (1–12 phases)
Input Voltage Range	4.5 V to 30 V - supports wide industrial and telecom input rails
Output Voltage Accuracy	±0.5% over –40°C to +85°C - ensures tight regulation for ASIC/FPGA core supplies
Current Sense Threshold	Programmable 24 mV to 85 mV - enables precision DCR or discrete R_SENSE sensing
Switching Frequency	250 kHz to 750 kHz (adjustable); sync range 175 kHz to 900 kHz - balances efficiency, size, and EMI
Min On-Time	65 ns typical - supports high VIN-to-low VOUT conversion (e.g., 12 V → 1.2 V at 500 kHz)
Thermal Shutdown	165°C with 25°C hysteresis - protects against sustained overload or poor heatsinking
Package	38-lead (5 mm × 7 mm) plastic QFN with exposed PGND pad - optimized for thermal performance and compact layout

Pinout & Package

Package: 38-lead (5 mm × 7 mm) plastic QFN with exposed thermal pad soldered to PGND. Pin count and function mapping are validated per Linear Technology LTC3811 datasheet Rev. F (2011).

Pin/Terminal	Circuit Role	Design Meaning
FB1, FB2	Error amplifier feedback inputs	Reference point for output voltage regulation; 0.6 V nominal setpoint; supports remote sensing via DIFF/OUT
COMP1, COMP2	Error amplifier outputs	Low-impedance op-amp outputs; must not be directly paralleled unless slave FB tied to INTVCC
SENSE1+/–, SENSE2+/–	Current sense differential inputs	Accept DCR or R_SENSE signals; common-mode range 0–3.5 V; enable accurate peak-current mode control
TG1, TG2	Top gate drivers	High-current NMOS drivers (1 A peak source); drive upper MOSFET gates with 20 ns rise time (3.3 nF load)
BG1, BG2	Bottom gate drivers	High-current NMOS drivers (1 A peak source); drive lower MOSFET gates with 20 ns rise time (3.3 nF load)
DIFF/IN+, DIFF/IN–	Differential remote sense inputs	High-precision (±6 mV offset), unity-gain inputs for Kelvin sensing at load; require matched PCB routing
CSOUT	Voltage positioning gm amplifier output	Bi-directional 5 mS transconductance output (QFN only); programs load-line droop via external resistor
PHASEMODE	Multiphase phase relationship control	Configures channel-to-channel (0°/120°/180°) and channel-to-CLKOUT (90°/60°/240°) phase offsets

Key Features

Feature	Design Value
Dual independent controllers	Enables ratiometric or sequenced start-up of core and I/O rails without external sequencing ICs
Programmable current sense threshold (24–85 mV)	Supports both low-value DCR sensing (reducing power loss) and discrete sense resistors (improving accuracy)
Voltage positioning (CSOUT, QFN only)	Provides programmable load-line droop (ΔV ∝ I_OUT) to maintain system stability under dynamic load transients
High-speed differential remote sense amplifier	Rejects PCB IR drop with >100 dB PSRR, enabling accurate regulation at point-of-load despite trace resistance
12-phase daisy-chain capability	CLKOUT and MODE/SYNC allow precise phase interleaving across multiple LTC3811s, reducing input/output ripple current
Integrated 6 V / 100 mA DRVCC LDO + EXTVCC switch	Reduces thermal stress by allowing external 5 V supply to power gate drivers, bypassing internal LDO

Applications

Network Server Core Supply	ASIC/FPGA High-Current I/O Rail
Use Scenario: Powering multi-core CPUs and memory interfaces in 1U/2U rack servers requiring <2 V, >100 A combined output. IC Role / Device Role / Timing Role: Dual-channel PolyPhase® controller managing two synchronized 2-phase or single 4-phase outputs with tracking and voltage positioning. Use Value: Enables <1% output deviation under 50 A/μs load steps via differential remote sensing and programmable load line.	Use Scenario: Delivering stable 1.8 V or 2.5 V I/O voltage to high-speed SerDes blocks in AI accelerators and networking ASICs. IC Role / Device Role / Timing Role: Independent second channel configured for forced CCM operation with soft-start and PGOOD sequencing. Use Value: Achieves <±0.5% regulation across –40°C to +85°C using internal reference and remote sense, eliminating need for external DAC trimming.
Low-Voltage Power Distribution Bus	High-Density Telecom Board Supply
Use Scenario: Generating distributed 3.3 V or lower intermediate bus voltages across backplane-mounted modules with strict IR-drop tolerance. IC Role / Device Role / Timing Role: Single-output, 6-phase configuration using CLKOUT daisy-chaining to minimize input capacitor RMS current. Use Value: Reduces total input capacitance by >50% versus single-phase design while maintaining <10 mV ripple at full load.	Use Scenario: Compact 12 V input to 1.2 V/60 A output on space-constrained telecom line cards with thermal constraints. IC Role / Device Role / Timing Role: Dual 2-phase operation with EXTVCC bypass and exposed QFN pad for direct thermal coupling to heatsink. Use Value: Delivers >92% peak efficiency at 60 A while limiting junction temperature to <110°C under continuous load.

Network Server Core Supply

ASIC/FPGA High-Current I/O Rail

Use Scenario: Powering multi-core CPUs and memory interfaces in 1U/2U rack servers requiring <2 V, >100 A combined output.

IC Role / Device Role / Timing Role: Dual-channel PolyPhase® controller managing two synchronized 2-phase or single 4-phase outputs with tracking and voltage positioning.

Use Value: Enables <1% output deviation under 50 A/μs load steps via differential remote sensing and programmable load line.

Use Scenario: Delivering stable 1.8 V or 2.5 V I/O voltage to high-speed SerDes blocks in AI accelerators and networking ASICs.

IC Role / Device Role / Timing Role: Independent second channel configured for forced CCM operation with soft-start and PGOOD sequencing.

Use Value: Achieves <±0.5% regulation across –40°C to +85°C using internal reference and remote sense, eliminating need for external DAC trimming.

Low-Voltage Power Distribution Bus

High-Density Telecom Board Supply

Use Scenario: Generating distributed 3.3 V or lower intermediate bus voltages across backplane-mounted modules with strict IR-drop tolerance.

IC Role / Device Role / Timing Role: Single-output, 6-phase configuration using CLKOUT daisy-chaining to minimize input capacitor RMS current.

Use Value: Reduces total input capacitance by >50% versus single-phase design while maintaining <10 mV ripple at full load.

Use Scenario: Compact 12 V input to 1.2 V/60 A output on space-constrained telecom line cards with thermal constraints.

IC Role / Device Role / Timing Role: Dual 2-phase operation with EXTVCC bypass and exposed QFN pad for direct thermal coupling to heatsink.

Use Value: Delivers >92% peak efficiency at 60 A while limiting junction temperature to <110°C under continuous load.

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-output multiphase controller applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
LTC3870IUFD#PBF	Single-channel, 6-phase capable; no voltage positioning; supports 4.5–38 V input; requires external clock for >750 kHz	Best suited for single-rail, ultra-high-current (>150 A) applications where dual outputs are unnecessary	Select when only one regulated rail is needed and higher input voltage range is required
ISL6322IRZ-T	Triple-channel, 3+3+1-phase; integrated MOSFET drivers; no EXTVCC option; 4.5–24 V input; supports Intel VR12.5	Targeted at x86 CPU VRMs with SMBus interface and processor-specific VID codes	Select for Intel-compatible platforms requiring serial digital interface and VID-based dynamic voltage scaling

Compared with LTC3870IUFD#PBF and ISL6322IRZ-T, the LTC3811EUHF#PBF uniquely provides dual independent controllers with voltage positioning (QFN only), differential remote sensing, and flexible 1–12-phase scalability - making it optimal for custom, non-VID, multi-rail embedded power systems demanding analog precision and layout flexibility.

Availability

LTC3811EUHF#PBF is available at Aetrix Electronics and suitable for network server power supplies, ASIC/FPGA core and I/O rails, and telecom board-level power distribution requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for LTC3811EUHF#PBF 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

Analog Devices acquired Linear Technology in 2017, inheriting its legacy of high-performance analog and power management ICs. Linear pioneered PolyPhase® multiphase architecture for high-current DC/DC conversion.

The LTC3811 belongs to Linear's high-efficiency synchronous buck controller product line, designed specifically for low-voltage, high-current point-of-load applications in datacenter, telecom, and industrial computing where precision regulation, thermal robustness, and phase scalability are critical.

FAQ

What is the minimum on-time specification for the LTC3811EUHF#PBF, and why does it matter?

The LTC3811EUHF#PBF has a typical minimum on-time of 65 ns. This parameter determines the lowest achievable output voltage at a given input voltage and switching frequency - for example, enabling 12 V input to 1.2 V output at 500 kHz (D = V_OUT/V_IN ≈ 10%, t_ON(MIN) = 65 ns → f_MAX ≈ 1/(D × t_ON(MIN)) ≈ 308 kHz). The LTC3811EUHF#PBF's 65 ns t_ON(MIN) supports high-frequency, high-step-down designs without pulse-skipping artifacts.

Does the LTC3811EUHF#PBF support differential remote sensing, and how is it implemented?

Yes, the LTC3811EUHF#PBF includes a dedicated high-precision differential remote sense amplifier with inputs DIFF/IN+ and DIFF/IN–, and output DIFF/OUT. It provides unity gain (0.995–1.005 V/V), ±6 mV offset, and >100 dB PSRR. To implement, connect DIFF/IN+ and DIFF/IN– directly to the positive/negative terminals of the load-side output capacitor, route traces as matched pairs, and feed DIFF/OUT into the FB pin via a resistor divider. This compensates for PCB trace IR drop, ensuring regulation accuracy at the load.

What is the function of the CSOUT pin on the LTC3811EUHF#PBF, and is it available in all packages?

The CSOUT pin is the output of the voltage positioning transconductance amplifier (gm = 5.0 mS), used to program intentional output voltage droop (ΔV ∝ I_OUT) for improved transient response and system stability. It is available only on the QFN package (LTC3811EUHF#PBF); the SSOP version (LTC3811EG#PBF) lacks this pin and voltage positioning capability. A small external resistor from CSOUT to SGND sets the droop slope - e.g., 10 mΩ yields 50 mV/A droop.

How does the PHASEMODE pin affect multiphase operation of the LTC3811EUHF#PBF?

The PHASEMODE pin on the LTC3811EUHF#PBF configures the phase relationship between Channel 1 and Channel 2 (0°, 120°, or 180°), and between Channel 1 and CLKOUT (90°, 60°, or 240°), enabling flexible interleaving for 2-, 3-, 4-, 6-, or 12-phase systems. This pin is exclusive to the QFN package; the SSOP version fixes channel-to-channel phase at 180° and channel-to-CLKOUT at 90°, limiting it to 2- and 4-phase topologies. The LTC3811EUHF#PBF thus offers superior phase flexibility for custom high-phase-count designs.

Can the LTC3811EUHF#PBF operate with both DCR and discrete sense resistors, and how is the sensing range selected?

Yes, the LTC3811EUHF#PBF supports both inductor DCR sensing and discrete sense resistors via its SENSE1+/– and SENSE2+/– inputs. The peak current sense threshold is programmed using the RNG1/RNG2 pins: grounding selects 24 mV, tying to INTVCC selects 50 mV, and applying 0.6–2.0 V linearly scales the threshold from 24 mV to 85 mV. This allows optimization for low-loss DCR sensing (e.g., 0.5 mΩ DCR → 25 mV drop at 50 A) or high-accuracy R_SENSE (e.g., 1 mΩ → 50 mV at 50 A), all within the LTC3811EUHF#PBF's validated operating range.

LTC3811EUHF#PBF Specifications

Product attributes: Attribute value

Manufacturer:: Analog Devices Inc.

Series:: PolyPhase®

Package/Case:: 38-WFQFN Exposed Pad

Packaging:: Tube

Product Status:: Active

Output Type:: Transistor Driver

Function:: Step-Down

Output Configuration:: Positive

Topology:: Buck

Number of Outputs:: 2

Output Phases:: 2

Voltage - Supply (Vcc/Vdd):: 4.5V ~ 30V

Frequency - Switching:: 250kHz ~ 750kHz

Duty Cycle (Max):: -

Synchronous Rectifier:: Yes

Clock Sync:: Yes

Serial Interfaces:: -

Control Features:: Current Limit, Enable, Phase Control, Power Good, Soft Start, Tracking

Operating Temperature:: -40°C ~ 85°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 38-QFN (5x7)

LTC3811EUHF#PBF FAQ

1.How can I place an order for LTC3811EUHF#PBF through Aetrix?

Please submit a Request for Quotation (RFQ) for LTC3811EUHF#PBF 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 LTC3811EUHF#PBF reliable?

The price and inventory of LTC3811EUHF#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3811EUHF#PBF is usually 5 days.

3.What payment methods are accepted for LTC3811EUHF#PBF?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3811EUHF#PBF transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for LTC3811EUHF#PBF?

LTC3811EUHF#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your LTC3811EUHF#PBF 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 LTC3811EUHF#PBF?

For technical support, including LTC3811EUHF#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3811EUHF#PBF requirements.

6.How does Aetrix verify that LTC3811EUHF#PBF is sourced from the original manufacturer or authorized distributors?

All LTC3811EUHF#PBF 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 LTC3811EUHF#PBF meets industry standards.

7.What is the process for return or replacement of LTC3811EUHF#PBF?

All LTC3811EUHF#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3811EUHF#PBF, 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 LTC3811EUHF#PBF part is unused and in its original packaging.

Return procedure for LTC3811EUHF#PBF:

1.Submit a request within 90 days.

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

Tech Hub

2026-09-03 Logic Level Shifter: How to Connect 3.3V and 5V Logic Safely

A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.

2026-09-03 74HC595 vs TPIC6B595: Output Drive, Pinout, Current, and Load Selection

The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…

2026-09-01 74HC595 Pinout, Timing, Output Current, and Applications

The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…

2026-09-01 Latch vs Flip-Flop: Timing, Differences and Design Choices

A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…

2026-08-30 D Latch Circuit: Truth Table, Timing, ICs and Applications

A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …

2026-08-28 SR Latch Explained: NOR and NAND Circuits, Truth Tables, and Applications

An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…

2026-08-27 Latch Circuit: SR and D Latches, Truth Tables, Timing, and Applications

Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…

2026-08-21 What Is an LED Driver? Types, Circuits, Dimming, and Selection

An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…

2026-08-18 Operational Amplifier (Op Amp): Basics, Configurations, Feedback and Applications

Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…

2026-08-14 Jumper Cables: How to Use, Connect and Choose Them Safely

Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…