My Inquiry
My Account
Analog Devices Inc. LTC3811EUHF#TRPBF
- Part No.:
- LTC3811EUHF#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 38-WFQFN Exposed Pad
- Datasheet:
-
LTC3811EUHF#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 38QFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,104
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LTC3811EUHF#TRPBF 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 features ±0.5% output voltage accuracy over temperature, programmable peak current sense threshold (24mV–85mV), and supports 1–12-phase operation via MODE/SYNC, CLKOUT, and PHASEMODE pins. Used in network server core/I/O supplies with 15A per channel.
For engineers reviewing the LTC3811EUHF#TRPBF datasheet, LTC3811EUHF#TRPBF pinout, LTC3811EUHF#TRPBF application, or LTC3811EUHF#TRPBF equivalent, key selection criteria include remote differential sensing capability, DCR or resistor-based current sensing, 250kHz–750kHz programmable switching frequency, and support for voltage positioning and ratiometric tracking in multi-rail systems.
Technical Context
The LTC3811EUHF#TRPBF implements fixed-frequency, peak current mode control with two independent high-bandwidth error amplifiers and a dedicated high-speed differential remote sense amplifier (gain = 1.000 V/V, offset ≤ ±6mV). Its multiphase architecture uses PLL synchronization and phase-programmable outputs (via PHASEMODE pin) to enable precise interleaving across up to 12 phases.
It integrates powerful internal gate drivers (1.0A peak source/sink, 0.9Ω RDS(ON)), a 6V DRVCC LDO with 100mA RMS output, and voltage positioning functionality (5.0mS transconductance) for load-line regulation-available only in the QFN package. The device supports both continuous and discontinuous conduction modes and includes thermal shutdown at 165°C with 25°C hysteresis.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage Range | Up to 3.3V; optimized for low-VOUT digital supply rails requiring tight regulation. |
| Input Voltage Range | 4.5V to 30V; supports wide-input industrial and telecom power buses. |
| Switching Frequency | 250kHz–750kHz programmable; enables optimization of efficiency vs. size trade-offs. |
| Current Sense Threshold | 24mV–85mV adjustable; accommodates DCR sensing or discrete shunt resistors. |
| Feedback Accuracy | ±0.5% over –40°C to +85°C; ensures stable core voltage under thermal stress. |
| Min On-Time | 65ns typical; supports high VIN-to-low VOUT conversion (e.g., 12V→1.2V) at high frequency. |
| Differential Sense Gain | 0.995–1.005 V/V; enables accurate remote voltage regulation at point-of-load. |
| Thermal Shutdown | 165°C with 25°C hysteresis; protects against sustained overload or poor heatsinking. |
Pinout & Package
The LTC3811EUHF#TRPBF is housed in a 38-lead (5mm × 7mm) plastic QFN package with exposed PGND pad soldered to PCB. Pin functions are validated per Linear Technology's official datasheet (3811f) and confirmed on the UHF package drawing.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SENSE1+/SENSE2+ | Positive current sense input | Accepts DCR or shunt voltage; common-mode range 0–3.5V; enables precision current-mode control. |
| FB1/FB2 | Error amplifier feedback input | Regulates output to 0.6V reference; supports local or remote sense via DIFF/IN+/-. |
| TG1/TG2 | Top gate driver output | Drives N-channel high-side MOSFETs; 1.0A peak source/sink, 20ns rise time (3300pF). |
| BG1/BG2 | Bottom gate driver output | Drives N-channel low-side MOSFETs; 1.0A peak source/sink, 20ns rise time (3300pF). |
| PHASEMODE | Multiphase phase programming | QFN-only pin; sets CH1–CH2 phase shift (180°/120°) and CH1–CLKOUT relationship (90°/240°). |
| CLKOUT | Multiphase daisy-chain clock | Enables synchronization of up to 12 phases across multiple LTC3811 devices. |
| CSOUT | Voltage positioning current output | QFN-only; 5.0mS transconductance; programs load-line droop via external resistor. |
| DIFF/IN+/DIFF/IN– | Differential remote sense inputs | High-precision inputs for Kelvin sensing at load; reject PCB trace IR drop. |
| SS/TRACK1/SS/TRACK2 | Soft-start & tracking control | 2.5μA internal charge current; supports ratiometric, coincident, or sequenced startup. |
| RUN1/RUN2 | Independent enable control | Logic-level ON/OFF control per channel; <0.3V low threshold, >1.8V high threshold. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent controllers | Enables separate regulation of core and I/O rails with independent soft-start, tracking, and fault management. |
| Programmable current sense threshold | 24mV–85mV range allows optimal noise immunity and power loss trade-off for DCR or shunt sensing. |
| High-speed differential remote sensing | ±6mV offset and 100dB PSRR ensure accurate load-point regulation despite PCB voltage drop. |
| Voltage positioning (QFN only) | 5.0mS transconductance gm amplifier enables programmable load-line droop to maintain stability under dynamic load. |
| Multiphase flexibility | Supports 1-, 2-, 3-, 4-, 6-, or 12-phase configurations via MODE/SYNC, CLKOUT, and PHASEMODE pins. |
| Low minimum on-time | 65ns tON(MIN) enables high-step-down ratios (e.g., 12V→1.2V) at 750kHz without pulse-skipping artifacts. |
Applications
| Network Server Core Supply | ASIC High-Current I/O Supply |
|---|---|
Use Scenario: Regulating CPU/GPU core voltage (e.g., 1.2V @ 15A) in dual-processor rack servers with strict transient response requirements. IC Role / Device Role / Timing Role: Dual-phase synchronous buck controller providing interleaved current sharing and fast load-step response. Use Value: Achieves <20μs load-step recovery (12.5A step) and ±0.5% output accuracy across –40°C to +85°C ambient. | Use Scenario: Powering FPGA or ASIC I/O banks (e.g., 1.5V @ 15A) requiring tight voltage tracking relative to core rail. IC Role / Device Role / Timing Role: Secondary controller configured for ratiometric tracking using SS/TRACK2 and FB1 feedback path. Use Value: Enables coincident startup and <±5mV tracking error between core and I/O rails during dynamic load transitions. |
| Low-Voltage Power Distribution | High-Density Telecom Board Supply |
Use Scenario: Generating multiple low-voltage rails (e.g., 2.0V, 1.5V, 1.2V) from a 12V intermediate bus in space-constrained base station modules. IC Role / Device Role / Timing Role: Multiphase controller operating in 4-phase mode to reduce input/output ripple and component count. Use Value: Reduces input capacitor RMS current by ~50% versus single-phase, enabling smaller 1206 ceramic capacitors. | Use Scenario: Delivering 15A per rail in NEBS-compliant telecom line cards where thermal density and EMI must be minimized. IC Role / Device Role / Timing Role: Synchronized 6-phase controller using external clock (MODE/SYNC) to align switching edges across multiple boards. Use Value: Lowers radiated emissions by spreading spectral energy and reduces thermal hot spots via interleaved phase currents. |
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#TRPBF | Single-channel, 4-phase capable; lacks second independent controller and voltage positioning (CSOUT). | Suitable for single-rail, higher-phase-count designs but cannot replace dual-rail tracking functionality. | Select when only one regulated output is needed and 4-phase interleaving suffices for current handling. |
| MP2918GL-Z | Fixed 2-phase operation; no PHASEMODE or CLKOUT; lower max frequency (1MHz); no differential remote sense amplifier. | Targeted at cost-sensitive consumer SSDs; lacks precision remote sensing and multiphase scalability. | Choose for simpler, lower-cost 2-phase applications where ±1% accuracy and basic sequencing suffice. |
Compared with LTC3870IUFD#TRPBF and MP2918GL-Z, the LTC3811EUHF#TRPBF uniquely delivers dual independent controllers with full voltage positioning, differential remote sensing, and scalable 1–12-phase operation-making it irreplaceable for high-accuracy, multi-rail server and telecom power systems.
Availability
LTC3811EUHF#TRPBF is available at Aetrix Electronics and suitable for network servers, high-current ASIC supplies, and low-voltage power distribution systems requiring stable component supply, long-term lifecycle support, and guaranteed parametric performance over –40°C to +85°C.
Supply support for LTC3811EUHF#TRPBF 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 and maintains full product support, documentation, and manufacturing continuity for all Linear-branded power ICs.
The LTC3811EUHF#TRPBF belongs to Linear's PolyPhase® controller family, designed specifically for high-efficiency, high-current, multi-phase DC/DC conversion in datacenter, telecom, and industrial computing applications.
FAQ
What is the minimum on-time specification for the LTC3811EUHF#TRPBF?
The LTC3811EUHF#TRPBF has a typical minimum on-time of 65ns, verified per datasheet Figure 3811 G04. This enables high-step-down conversion (e.g., 12V input to 1.2V output) at 750kHz without pulse-skipping instability. The parameter is guaranteed by design and applies across the full –40°C to +85°C operating junction temperature range.
Does the LTC3811EUHF#TRPBF support differential remote sensing?
Yes, the LTC3811EUHF#TRPBF includes a dedicated high-speed differential remote sense amplifier with inputs DIFF/IN+ and DIFF/IN–, and output DIFF/OUT. Its gain is 0.995–1.005 V/V and input offset is ±6mV, enabling accurate point-of-load regulation. This function is fully supported in the UHF QFN package and documented in the LTC3811EUHF#TRPBF datasheet Section "Differential Amplifier".
Can the LTC3811EUHF#TRPBF operate in discontinuous conduction mode (DCM)?
Yes, the LTC3811EUHF#TRPBF supports selectable continuous conduction mode (CCM) or discontinuous conduction mode (DCM). DCM is enabled by pulling the MODE/SYNC pin to SGND, while CCM is selected by connecting MODE/SYNC to INTVCC. This behavior is specified in the "Features" section and confirmed in Electrical Characteristics Table under "Selectable CCM or DCM Operation".
What is the purpose of the PHASEMODE pin on the LTC3811EUHF#TRPBF?
The PHASEMODE pin on the LTC3811EUHF#TRPBF programs the phase relationship between Channel 1 and Channel 2 (180°, 180°, or 120°) and between Channel 1 and CLKOUT (90°, 60°, or 240°). This pin is exclusive to the QFN package (UHF) and is required for configuring 3-, 6-, or 12-phase systems. Its function is detailed in Note 9 of the LTC3811EUHF#TRPBF datasheet.
Is voltage positioning (load-line regulation) available on the LTC3811EUHF#TRPBF?
Yes, voltage positioning is available on the LTC3811EUHF#TRPBF via the CSOUT pin, which is present only in the QFN (UHF) package. It provides a 5.0mS transconductance amplifier output that sinks or sources current proportional to (SENSE+ – SENSE–), allowing programmable output droop under load. This feature is explicitly listed in the "Features" section and electrical characteristics table for the UHF variant.
LTC3811EUHF#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- PolyPhase®
- Package/Case:
- 38-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- 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#TRPBF FAQ
1.How can I place an order for LTC3811EUHF#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3811EUHF#TRPBF 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#TRPBF reliable?
The price and inventory of LTC3811EUHF#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3811EUHF#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3811EUHF#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3811EUHF#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3811EUHF#TRPBF?
LTC3811EUHF#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3811EUHF#TRPBF 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#TRPBF?
For technical support, including LTC3811EUHF#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3811EUHF#TRPBF requirements.
6.How does Aetrix verify that LTC3811EUHF#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3811EUHF#TRPBF 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#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3811EUHF#TRPBF?
All LTC3811EUHF#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3811EUHF#TRPBF, 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#TRPBF part is unused and in its original packaging.
Return procedure for LTC3811EUHF#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LTC3811EUHF#TRPBF Tags
-
UCC28C45DR
Texas Instruments
-
UCC28C40DR
Texas Instruments
-
UCC28C43DR
Texas Instruments
-
ZXSC410E6TA
Diodes Incorporated
-
LM3524DMX/NOPB
Texas Instruments
-
LM3489MMX/NOPB
Texas Instruments
-
MIC2102YML-TR
Microchip Technology
-
LM5148RGYR
Texas Instruments
-
TL598CDR
Texas Instruments
-
LM5155DSSR
Texas Instruments
-
LM25085MYX/NOPB
Texas Instruments
-
UCC2813DTR-0
Texas Instruments
Tech Hub
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.
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…
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…
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…
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 …
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…
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…
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…
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…
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…
