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Analog Devices Inc. LTC3875IUJ#TRPBF
- Part No.:
- LTC3875IUJ#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 40-WFQFN Exposed Pad
- Datasheet:
-
LTC3875IUJ#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 40QFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,133
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Product details
Overview
LTC3875IUJ#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 enables low-DCR inductor sensing (10–30 mV programmable threshold), DCR temperature compensation, and thermal balancing across phases. Designed for high-current server and telecom power supplies, it delivers precise 0.6 V ±0.5% output regulation from 4.5 V to 38 V input.
For engineers reviewing the LTC3875IUJ#TRPBF datasheet, LTC3875IUJ#TRPBF pinout, LTC3875IUJ#TRPBF application, or LTC3875IUJ#TRPBF equivalent, key selection considerations include its dual-phase 180° interleaving, programmable 250–720 kHz switching frequency, remote differential sensing per channel, ±7.5% PGOOD window, and 40-lead 6 mm × 6 mm QFN package with exposed thermal pad.
Technical Context
The LTC3875IUJ#TRPBF implements current-mode control with two independent error amplifiers and dual high-speed remote-sense differential amplifiers-each with dedicated VOSNS+/VOSNS− inputs and ±0.5% reference accuracy over –40°C to 125°C. Its unique architecture enhances current-sense SNR for ultra-low-DCR inductors (e.g., 0.32 mΩ), reducing switching jitter and enabling stable operation at 60 A per phase.
It supports phase-lockable operation via MODE/PLLIN and CLKOUT pins, allowing up to 12-phase synchronization. Thermal balancing is implemented through TCOMP1/2, TRSET1/2, and TAVG pins, enabling per-phase current adjustment to equalize thermal stress in multi-IC configurations-critical for high-density DC power distribution systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5 V to 38 V - supports wide bus voltages including 5 V, 12 V, 24 V, and 36 V industrial and telecom rails. |
| Output Voltage Accuracy | ±0.5% at 0.6 V reference - ensures tight regulation for sub-1 V CPU/GPU core supplies without external calibration. |
| Current Sense Threshold | Programmable 10–30 mV (DC mode) - enables use of <1 mΩ DCR inductors while maintaining noise immunity and foldback protection. |
| Switching Frequency | 250–720 kHz (via FREQ pin) - balances efficiency vs. size; supports forced CCM, Burst Mode, or pulse-skipping via MODE/PLLIN. |
| Thermal Operating Range | –40°C to 125°C junction - qualified for industrial and extended-temperature embedded power applications. |
| Package | 40-lead 6 mm × 6 mm QFN (UJ), 0.5 mm pitch, exposed PGND pad - optimized for thermal dissipation in high-current layouts. |
| Phase Configuration | Dual 180° interleaved channels - cuts input ripple current by ~70%, reducing required bulk capacitance and EMI filtering. |
Pinout & Package
Package: 40-lead plastic QFN (6 mm × 6 mm, 0.5 mm pitch), exposed SGND/PGND thermal pad (Pin 41) requiring PCB soldering for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| TK/SS1 (Pin 1) | Channel 1 soft-start/tracking input | Internal 1.25 µA current charges external capacitor to ramp output voltage; enables voltage tracking with master/slave configuration. |
| VOSNS1+ / VOSNS1− (Pins 2,3) | Channel 1 remote sense differential inputs | Connect across output resistor divider to reject PCB IR drop; enables <±2 mV load regulation error at point-of-load. |
| ITH1 (Pin 4) | Channel 1 current limit threshold | Controls peak inductor current via error amplifier output; used for loop compensation and current foldback programming. |
| TAVG (Pin 13) | Average temperature summing node | Resistor-to-ground sets summed thermal current for multi-IC thermal balancing; float to disable function. |
| FREQ (Pin 15) | Oscillator frequency programming | 10 µA sink current; resistor-to-ground sets 250–720 kHz frequency - critical for EMI compliance and layout optimization. |
| RUN1 / RUN2 (Pins 16,34) | Independent channel enable inputs | 1.22 V threshold with 80 mV hysteresis; supports staggered startup, fault isolation, and dynamic power sequencing. |
| PGOOD (Pin 19) | Open-drain power-good indicator | Asserts low when either output deviates >±7.5% from setpoint after 20 µs mask timer - enables system-level power sequencing. |
| CLKOUT (Pin 31) | Synchronization clock output | Phase-selectable (60°/90°/120° via PHASMD) - enables deterministic timing across multiple LTC3875s in 6-, 12-phase systems. |
| SGND/PGND (Pin 41) | Signal/power ground reference | Exposed thermal pad must be soldered to large copper pour - provides low-inductance return path for gate drivers and high di/dt currents. |
Key Features
| Feature | Design Value |
|---|---|
| Dual 180° interleaved controllers | Reduces input RMS current by ~70%, cutting input capacitor count and size in high-power 12 V–in systems. |
| Low-DCR current sensing (10–30 mV) | Enables use of 0.32 mΩ inductors without added sense resistors - improves full-load efficiency by 1–2% in 60 A designs. |
| Per-channel DCR temperature compensation | TCOMP1/2 pins accept NTC thermistors near inductors to maintain constant current limit across –40°C to 125°C ambient. |
| Thermal balancing across phases/ICs | TAVG summation allows automatic per-phase current redistribution - prevents hot-spotting in parallel-phase or multi-IC stacks. |
| Programmable fast transient response (IFAST) | Channel 2 only: resistor-to-ground on IFAST pin adjusts load-step response aggressiveness without affecting stability. |
| Robust protection suite | Includes short-circuit soft recovery, output overvoltage lockout (±7.5%), undervoltage lockout (3.7 V), and thermal shutdown (160°C). |
Applications
| Server VR13/VR14 Core Power | Telecom 48 V Intermediate Bus Converter |
|---|---|
|
Use Scenario: Dual-phase 1.2 V @ 60 A supply for high-end Xeon or EPYC processors with strict transient response and thermal constraints. IC Role / Device Role / Timing Role: Primary dual-phase synchronous buck controller managing gate drive, current sensing, and thermal balancing across two parallel phases. Use Value: Achieves >93% efficiency at full load using 0.32 mΩ DCR inductors and eliminates need for discrete current-sense resistors - saving board space and BOM cost. |
Use Scenario: 48 V to 12 V intermediate bus converter in 5G base station power shelves requiring high reliability and low EMI. IC Role / Device Role / Timing Role: Interleaved 2-phase controller synchronizing to system clock via MODE/PLLIN to suppress conducted emissions in dense RF environments. Use Value: 180° phase shift reduces input ripple current amplitude by 70%, allowing smaller input capacitors and meeting EN55032 Class B limits without shielding. |
| Industrial PLC Power Module | High-Density DC Power Distribution System |
|
Use Scenario: Ruggedized 24 V input to 3.3 V/5 V dual-output supply for programmable logic controllers operating in –40°C to 85°C ambient. IC Role / Device Role / Timing Role: Dual-output controller with independent RUN1/RUN2 enables sequenced startup and fault containment between I/O and logic rails. Use Value: ±0.5% output accuracy and remote sensing ensure stable microcontroller operation despite long PCB traces and connector voltage drops. |
Use Scenario: Multi-board 12 V distribution architecture using four LTC3875s in 12-phase configuration for AI accelerator racks. IC Role / Device Role / Timing Role: Master-slave synchronized controller providing CLKOUT and PHASMD-programmed phase alignment across boards. Use Value: TAVG-based thermal balancing maintains uniform current sharing across 12 phases - preventing premature failure of single-phase modules under uneven thermal loading. |
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 |
|---|---|---|---|
| LTC3873EUH#TRPBF | Single-output, no thermal balancing or DCR temperature compensation; 32-lead 5 mm × 5 mm QFN. | Limited to simpler, lower-current single-rail designs without multi-phase coordination needs. | Select only if dual output and thermal management are unnecessary - saves cost but sacrifices scalability and precision. |
| MP2960AGQSE-LF-Z | Monolithic dual-phase controller (integrated MOSFETs); fixed 600 kHz frequency; no CLKOUT or PHASMD. | Targeted at space-constrained consumer/edge AI applications where integration outweighs flexibility. | Choose for compactness and reduced external component count, but avoid where system-level synchronization or thermal balancing is required. |
Compared with LTC3875IUJ#TRPBF, LTC3873EUH#TRPBF lacks dual-output coordination and thermal features, while MP2960AGQSE-LF-Z trades programmability and multi-IC scalability for monolithic simplicity - making LTC3875IUJ#TRPBF optimal for high-reliability, thermally managed, multi-phase infrastructure power.
Availability
LTC3875IUJ#TRPBF is available at Aetrix Electronics and suitable for server VRMs, telecom intermediate bus converters, and industrial PLC power modules requiring stable component supply, extended temperature qualification, and long-term lifecycle support.
Supply support for LTC3875IUJ#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 LTC3875IUJ#TRPBF belongs to Linear's PolyPhase® synchronous controller family, engineered specifically for high-current, multi-phase DC/DC conversion in datacenter, telecom, and industrial infrastructure where thermal balance, low-DCR sensing, and precise voltage regulation are critical.
FAQ
What is the maximum supported switching frequency for the LTC3875IUJ#TRPBF?
The LTC3875IUJ#TRPBF supports a programmable switching frequency range of 250 kHz to 720 kHz via the FREQ pin, with typical nominal operation at 500 kHz. This range allows designers to optimize between efficiency (lower frequencies) and component size/EMI (higher frequencies), and remains stable across the full –40°C to 125°C operating junction temperature range.
Does the LTC3875IUJ#TRPBF require external current-sense resistors?
No - the LTC3875IUJ#TRPBF is designed for low-DCR inductor sensing and does not require external current-sense resistors. It uses integrated AC/DC current comparators (SNSA+/SNSD+/SNS− pins) to measure inductor DCR voltage drop, supporting thresholds from 10 mV to 30 mV with built-in temperature compensation via TCOMP1/2 pins.
How does thermal balancing work on the LTC3875IUJ#TRPBF?
The LTC3875IUJ#TRPBF implements thermal balancing by mirroring temperature-dependent currents from TCOMP1/2 pins onto TRSET1/2, then summing them at TAVG. When ENTMPB is grounded, the controller adjusts per-phase current to equalize average die temperature - essential for multi-IC parallel operation where uneven thermal loading could cause premature failure.
Can the LTC3875IUJ#TRPBF synchronize with other power controllers?
Yes - the LTC3875IUJ#TRPBF supports full system-level synchronization via its MODE/PLLIN pin (accepts external clock input) and CLKOUT pin (programmable phase output). PHASMD pin selects relative phase (60°/90°/120°), enabling deterministic timing across up to 12 phases using multiple LTC3875IUJ#TRPBF devices in master-slave configurations.
What is the purpose of the EXTVCC pin on the LTC3875IUJ#TRPBF?
The EXTVCC pin on the LTC3875IUJ#TRPBF allows bypassing the internal 5.5 V LDO regulator by supplying an external 4.7–6 V source - improving efficiency and reducing thermal load during high-current operation. When active, EXTVCC must always be ≤ VIN and applied after VIN to prevent reverse current flow through the internal switch body diode.
LTC3875IUJ#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 (6x6)
LTC3875IUJ#TRPBF FAQ
1.How can I place an order for LTC3875IUJ#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3875IUJ#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 LTC3875IUJ#TRPBF reliable?
The price and inventory of LTC3875IUJ#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3875IUJ#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3875IUJ#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3875IUJ#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3875IUJ#TRPBF?
LTC3875IUJ#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3875IUJ#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 LTC3875IUJ#TRPBF?
For technical support, including LTC3875IUJ#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3875IUJ#TRPBF requirements.
6.How does Aetrix verify that LTC3875IUJ#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3875IUJ#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 LTC3875IUJ#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3875IUJ#TRPBF?
All LTC3875IUJ#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3875IUJ#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 LTC3875IUJ#TRPBF part is unused and in its original packaging.
Return procedure for LTC3875IUJ#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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