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Analog Devices Inc. LTC3875IUH#TRPBF
- Part No.:
- LTC3875IUH#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 40-WFQFN Exposed Pad
- Datasheet:
-
LTC3875IUH#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 40QFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,001
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Product details
Overview
LTC3875IUH#TRPBF from Analog Devices (formerly Linear Technology) is a dual-output, 2-phase synchronous step-down DC/DC controller driving all-N-channel MOSFET stages. It delivers precise 0.6V ±0.5% output voltage accuracy, supports 4.5V–38V input, enables low-DCR current sensing down to 10mV threshold, and features DCR temperature compensation and thermal balancing for multichip 60A server power rails.
For engineers reviewing the LTC3875IUH#TRPBF datasheet, LTC3875IUH#TRPBF pinout, LTC3875IUH#TRPBF application, or LTC3875IUH#TRPBF equivalent, key selection criteria include phase-lockable 250–720kHz operation, dual remote-sense differential amplifiers, programmable current limit via ILIM, clock input/output for up to 12-phase scaling, and thermal balancing support across multiple ICs in high-density power systems.
Technical Context
The LTC3875IUH#TRPBF implements constant-frequency current-mode control with two independent 180°-phased channels, each using a transconductance error amplifier (gm = 2.2 mmho) and a precision 0.6V reference (±0.5% over –40°C to 125°C). Its unique architecture enhances current-sense signal-to-noise ratio for ultra-low-DCR inductors (e.g., 0.32mΩ), reducing switching jitter and enabling high-efficiency, high-current designs.
It integrates dual differential remote-sense amplifiers (VOSNS1+/–, VOSNS2+/–), programmable DCR temperature compensation via TCOMP1/2 pins, and thermal balancing through TAVG summation-allowing per-phase current adjustment to minimize thermal stress in paralleled configurations. The device supports forced CCM, Burst Mode™, or pulse-skipping via MODE/PLLIN and includes short-circuit soft recovery and output overvoltage protection.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5V to 38V - supports wide bus voltages including 12V, 24V, and 36V industrial/telecom rails. |
| Output Voltage Accuracy | ±0.5% at 0.6V reference - ensures tight regulation for sub-1.2V CPU/GPU core supplies. |
| Current Sense Threshold | 10mV to 30mV (programmable via ILIM) - enables use of ultra-low-DCR inductors without external sense resistors. |
| Switching Frequency Range | 250kHz to 720kHz (phase-lockable) - allows EMI optimization and multi-phase synchronization up to 12 phases. |
| Operating Temperature | –40°C to +125°C (industrial grade) - validated for continuous operation in thermally demanding server and telecom environments. |
| Package | 40-lead 5mm × 5mm QFN (UH), 0.4mm pitch - compact footprint with exposed thermal pad (Pin 41 = SGND/PGND) for efficient heat dissipation. |
| Thermal Balancing | Enabled via ENTMPB, TCOMP1/2, TRSET1/2, and TAVG - dynamically adjusts per-phase current to equalize thermal stress across paralleled controllers. |
Pinout & Package
Package: 40-lead plastic QFN (5mm × 5mm, 0.4mm pitch), exposed thermal pad (Pin 41 = SGND/PGND), RoHS-compliant, tape-and-reel (TRPBF).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| TK/SS1, TK/SS2 (1, 8) | Soft-start & tracking input | Internal 1.25µA current charges external capacitor to ramp output voltage; enables coordinated startup with other rails. |
| VOSNS1+, VOSNS2+ (2, 6) | Remote sense positive input | Connects to top of output resistor divider for accurate load-point voltage regulation, rejecting PCB IR drop. |
| VOSNS1–, VOSNS2– (3, 7) | Remote sense negative input | Connects to output capacitor negative terminal - completes Kelvin sensing loop for true load voltage feedback. |
| ITH1, ITH2 (4, 5) | Error amplifier output / current threshold | Voltage sets peak inductor current; used for loop compensation and current limiting in closed-loop operation. |
| FREQ (15) | Oscillator programming | 10µA sink current - resistor to ground sets frequency from 250kHz to 720kHz; also accepts external clock for PLL sync. |
| CLKOUT (31) | Phase-programmable clock output | Drives downstream controllers; phase offset (60°/90°/120°) set by PHASMD pin for optimal multiphase interleaving. |
| PGOOD (19) | Power-good open-drain output | Asserts low when either channel's output deviates >±7.5% from target - provides system-level rail sequencing and fault signaling. |
| ENTMPB (18) | Thermal balancing enable | Ground to activate per-phase current redistribution; critical for paralleling multiple LTC3875s in high-current (>100A) applications. |
Key Features
| Feature | Design Value |
|---|---|
| Dual 180°-phased N-channel synchronous drive | Reduces input ripple current by ~70% vs single-phase, cutting required bulk capacitance and lowering EMI. |
| Low-DCR current sensing (10–30mV range) | Eliminates power loss and board space of discrete current-sense resistors; supports <0.5mΩ inductor DCR. |
| Programmable DCR temperature compensation | Compensates inductor DCR drift over temperature using external NTC on TCOMP pins - maintains accurate current limit across –40°C to 125°C. |
| Dual true remote sensing differential amplifiers | Rejects PCB trace resistance errors - ensures ±0.5% output accuracy even with >100mΩ interconnect impedance. |
| Thermal balancing across multiple ICs | Equalizes per-phase current in paralleled configurations via TAVG summation - prevents thermal runaway and extends system lifetime. |
| Phase-lockable clock I/O (CLKOUT/MODE/PLLIN) | Enables deterministic interleaving of up to 12 phases across multiple LTC3875s - essential for >100A VR13/VR14 server regulators. |
Applications
| Server Core Voltage Regulation | Telecom Base Station Power |
|---|---|
Use Scenario: Dual 1.2V/60A output for high-performance CPU/GPU cores in 1U rack servers with strict thermal and efficiency requirements. IC Role / Device Role / Timing Role: Dual-phase synchronous buck controller managing parallel N-channel MOSFETs, providing precise 0.6V reference tracking and thermal-balanced current sharing. Use Value: Enables >94% peak efficiency at 60A with low-DCR inductors, reduces input capacitance by 50%, and prevents hot-spotting via real-time per-phase current adjustment. | Use Scenario: Distributed 3.3V/5V intermediate bus conversion in macro/micro base stations requiring high reliability and EMI control. IC Role / Device Role / Timing Role: Dual-output controller operating in forced CCM mode with phase-shifted switching to suppress conducted emissions on shared power planes. Use Value: Achieves <10mVpp output ripple at full load, meets EN55022 Class B limits, and supports seamless firmware updates via PGOOD sequencing. |
| Industrial DC Power Distribution | High-Density FPGA/ASIC Power |
Use Scenario: 12V-to-1.8V/1.0V dual-rail conversion for programmable logic and data acquisition modules in factory automation systems. IC Role / Device Role / Timing Role: Synchronous step-down controller with adjustable soft-start (TK/SS) and output overvoltage protection (PGOOD) for safe cold-start under partial load. Use Value: Guarantees monotonic startup, prevents latch-up during brown-out, and maintains regulation during 10A/µs load transients via fast transient mode (IFAST). | Use Scenario: Multiphase core supply for 28nm/16nm FPGAs with dynamic voltage/frequency scaling (DVFS) and tight transient response demands. IC Role / Device Role / Timing Role: Phase-locked dual controller synchronized to system clock (via MODE/PLLIN), supporting burst-mode operation during idle cycles. Use Value: Delivers <500ns response to 80% load steps, cuts quiescent current to 5mA at no load, and enables deep power-down states without rail collapse. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-phase synchronous buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3873EUJ#TRPBF | Single-output, 40-lead 6mm×6mm QFN; lacks thermal balancing, DCR tempco, and CLKOUT; max freq 600kHz. | Suitable only for non-paralleled, lower-current (<30A) applications without multiphase coordination needs. | Select only if cost-sensitive and thermal balancing/multiphase sync are unnecessary. |
| ISL95812IRZ-T | Single-chip dual-phase controller with integrated drivers; no external DCR tempco support; fixed 0.6V ref (±1%); 32-pin QFN. | Targeted at notebook VRMs; lacks remote sensing, programmable current limit, and industrial temp range. | Prefer for consumer-grade portable designs where integration outweighs precision and ruggedness. |
Compared with LTC3873EUJ#TRPBF and ISL95812IRZ-T, the LTC3875IUH#TRPBF uniquely combines dual 180°-phased control, DCR temperature compensation, thermal balancing, and phase-lockable clock I/O - making it the only option qualified for high-reliability, high-current, multiphase server and telecom power systems requiring long-term stability across temperature.
Availability
LTC3875IUH#TRPBF is available at Aetrix Electronics and suitable for server core voltage regulation, telecom base station power, and industrial DC power distribution requiring stable component supply, extended temperature operation, and long-term lifecycle support.
Supply support for LTC3875IUH#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 its high-performance analog and power management portfolio with rigorous automotive- and industrial-grade qualification.
The LTC3875IUH#TRPBF belongs to Linear's PolyPhase® synchronous controller family, designed specifically for high-efficiency, high-current, multiphase DC/DC conversion in datacenter, networking, and telecom infrastructure.
FAQ
What is the operating temperature range for the LTC3875IUH#TRPBF?
The LTC3875IUH#TRPBF is rated for continuous operation from –40°C to +125°C junction temperature. This industrial-grade specification is verified across process corners and ensures reliable performance in thermally constrained server and telecom equipment. The UH package has θJA = 44°C/W, and proper PCB thermal design (exposed pad soldering, thermal vias) is required to maintain TJ ≤ 125°C at full load.
Does the LTC3875IUH#TRPBF support remote voltage sensing?
Yes, the LTC3875IUH#TRPBF includes two dedicated differential remote-sense amplifier pairs: VOSNS1+/– and VOSNS2+/–. Each pair measures the voltage directly at the load point, rejecting PCB trace resistance errors. When properly implemented with Kelvin connections, this feature ensures ±0.5% output voltage accuracy regardless of interconnect impedance - critical for sub-1.2V digital rail regulation.
How does the thermal balancing function work on the LTC3875IUH#TRPBF?
The LTC3875IUH#TRPBF implements thermal balancing by mirroring currents from TCOMP1/2 pins (connected to NTC thermistors near inductors) into TRSET1/2, then summing them at TAVG. When ENTMPB is grounded, the controller adjusts per-phase ITH thresholds to equalize average channel temperatures. This prevents thermal runaway in paralleled configurations and extends system lifetime - a capability not found in most dual-phase controllers.
Can the LTC3875IUH#TRPBF be synchronized to an external clock?
Yes, the LTC3875IUH#TRPBF supports external synchronization via the MODE/PLLIN pin. Applying a clean clock signal (250–720kHz) to this pin forces the internal oscillator into phase-locked operation, eliminating beat frequencies in multi-rail systems. The integrated PLL compensation network eliminates need for external loop filters, simplifying layout while maintaining lock stability across temperature and voltage.
What is the purpose of the SNSD1+/SNSD2+ pins on the LTC3875IUH#TRPBF?
The SNSD1+/SNSD2+ pins on the LTC3875IUH#TRPBF serve as DC current sense comparator inputs for low-DCR inductor networks. When used with SNSA1+/SNSA2+ and SNS1–/SNS2–, they enable a novel skewed DCR sensing topology that boosts AC ripple voltage by 5× - improving signal-to-noise ratio and enabling accurate current measurement down to 10mV threshold without external resistors.
LTC3875IUH#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 40-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 ~ 38V
- Frequency - Switching:
- 250kHz ~ 720kHz
- Duty Cycle (Max):
- -
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Current Limit, Enable, Frequency Control, Phase Control, Power Good, Soft Start, Tracking
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 40-QFN (5x5)
LTC3875IUH#TRPBF FAQ
1.How can I place an order for LTC3875IUH#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3875IUH#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 LTC3875IUH#TRPBF reliable?
The price and inventory of LTC3875IUH#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3875IUH#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3875IUH#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3875IUH#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3875IUH#TRPBF?
LTC3875IUH#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3875IUH#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 LTC3875IUH#TRPBF?
For technical support, including LTC3875IUH#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3875IUH#TRPBF requirements.
6.How does Aetrix verify that LTC3875IUH#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3875IUH#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 LTC3875IUH#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3875IUH#TRPBF?
All LTC3875IUH#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3875IUH#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 LTC3875IUH#TRPBF part is unused and in its original packaging.
Return procedure for LTC3875IUH#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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