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Analog Devices Inc. LTC3865EUH#TRPBF
- Part No.:
- LTC3865EUH#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 32-WFQFN Exposed Pad
- Datasheet:
-
LTC3865EUH#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 32QFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,827
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Product details
Overview
LTC3865EUH#TRPBF from Analog Devices (formerly Linear Technology) is a dual, 2-phase synchronous step-down DC/DC controller driving all-N-channel MOSFET stages. It delivers precise 1.5V/15A and 1.2V/15A outputs with 180° phase interleaving, 4.5V–38V input range, and pin-selectable VID programming. Used in high-density server VRMs and telecom power distribution systems.
For engineers reviewing the LTC3865EUH#TRPBF datasheet, LTC3865EUH#TRPBF pinout, LTC3865EUH#TRPBF application, or LTC3865EUH#TRPBF equivalent, key selection criteria include dual-phase current-mode control, OPTI-LOOP® compensation for wide output capacitance tolerance, independent track/soft-start pins, adjustable current limit via ILIM pin, and phase-lockable 250kHz–770kHz operation.
Technical Context
The LTC3865EUH#TRPBF implements constant-frequency current-mode control with two independent error amplifiers (EA), transconductance gm = 2.2 mmho, and dual ITH pins setting peak inductor current per channel. Its 180° out-of-phase operation reduces input/output ripple and improves thermal distribution across PCBs.
It supports three light-load modes-Burst Mode®, pulse-skipping, and forced continuous conduction-selected via MODE/PLLIN pin voltage. The device integrates dual N-channel gate drivers (TG/BG) with 2.6Ω pull-up / 1.5Ω pull-down on TG and 3Ω/1.4Ω on BG, plus internal 5V INTVCC regulator (4.8V–5.2V) and EXTVCC switchover at 4.7V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5V to 38V - supports wide industrial and telecom input rails without external pre-regulation |
| Output Voltage Programming | 0.6V to 5V via 2-pin VID strapping - enables precise, resistor-free VOUT setup for CPU/GPU core rails |
| Switching Frequency Range | 250kHz to 770kHz (phase-lockable) - balances efficiency, size, and EMI in high-current designs |
| Current Sense Threshold | 24mV to 82mV (E-grade, configurable via ILIM pin) - sets accurate overcurrent protection with DCR or RSENSE sensing |
| Efficiency | Up to 95% - achieved through low-Rds(on) gate drive, minimized dead-time losses, and optimized driver timing |
| Soft-Start Current | 1.3μA (typical) - provides controlled, predictable output ramp rate using external capacitor on TK/SS pins |
| Power Good Accuracy | ±10% window on VOSENSE - ensures reliable system sequencing and fault detection for dual-rail supplies |
Pinout & Package
Package: 32-lead (5mm × 5mm) plastic QFN with exposed SGND pad (Pin 33), rated for –40°C to +125°C junction temperature. Thermal resistance θJA = 34°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VOSENSE1, VOSENSE2 (Pins 1, 8) | Error amplifier feedback inputs | Accept remote-sensed output voltage or external divider signals; enable precision regulation under load transients |
| TK/SS1, TK/SS2 (Pins 2, 7) | Soft-start and tracking control | Internal 1.3μA current charges external capacitor to ramp VOUT; supports master-slave voltage tracking |
| ITH1, ITH2 (Pins 3, 6) | Error amplifier output / current threshold | Directly sets peak inductor current per phase; interface point for loop compensation network |
| VID11, VID12, VID21, VID22 (Pins 4, 5, 12, 28) | Output voltage selection inputs | Four logic-level pins (INTVCC/GND/float) configure nine discrete VOUT values from 0.6V to 5V |
| ILIM (Pin 13) | Current sense threshold range select | Configures max sense voltage to 24mV/44mV/68mV (E-grade); critical for accurate OCP calibration |
| PGOOD (Pin 14) | Co-bonded power-good indicator | Open-drain output pulled low if either channel exceeds ±10% regulation window after 100μs blanking |
| MODE/PLLIN (Pin 27) | Light-load mode select & sync input | DC level selects Burst/Pulse-Skip/Continuous mode; AC clock synchronizes oscillator to external source |
| FREQ (Pin 29) | Oscillator frequency set | 7.5μA sink current into external resistor sets nominal frequency (e.g., 162kΩ → 500kHz) |
| TG1, TG2 / BG1, BG2 (Pins 25,16 / 23,19) | Top/bottom gate drivers | Drive N-MOSFET gates with fast rise/fall times (25ns) and matched dead-time control to prevent shoot-through |
| SW1, SW2 (Pins 26, 15) | Switch node connections | Interface directly to inductor high-side nodes; support bootstrap operation up to 40V swing |
Key Features
| Feature | Design Value |
|---|---|
| Dual 180° phased controllers | Reduces input RMS current by ~30% and output voltage ripple amplitude by >70% vs single-phase design |
| OPTI-LOOP® compensation | Enables stable loop response across 10× variation in output capacitor ESR and 100× capacitance range |
| RSENSE or DCR current sensing | Supports both discrete shunt resistors and lossless inductor DCR networks - lowers heat dissipation and BOM cost |
| Independent track/soft-start | Allows staggered startup of dual rails or precise voltage ramping to meet ASIC/FPGA sequencing requirements |
| Output overvoltage protection | Detects VOSENSE excursion beyond ±10%; disables top FET and asserts PGOOD within 100μs |
| Adjustable current foldback | Reduces MOSFET conduction losses during short-circuit by lowering ITH reference as VOUT collapses |
Applications
| Server Core Voltage Regulation | Telecom Intermediate Bus Converter |
|---|---|
Use Scenario: Dual-rail 1.5V/15A and 1.2V/15A supply for multi-core Xeon or AMD EPYC processors in 1U rack servers. IC Role / Device Role / Timing Role: Primary dual-phase buck controller managing transient response, phase interleaving, and rail sequencing. Use Value: 180° phasing cuts input capacitor RMS current, enabling smaller 1210-size ceramics; VID strapping eliminates trim-pot tuning. |
Use Scenario: 48V-to-12V intermediate bus conversion in 5G base station power shelves with strict efficiency targets. IC Role / Device Role / Timing Role: High-efficiency, wide-input synchronous controller operating in forced continuous mode at full load. Use Value: 95% peak efficiency at 15A reduces thermal load on heatsinks; EXTVCC support allows self-powered operation from downstream 12V rail. |
| FPGA Power Management Unit | Industrial PLC I/O Module Supply |
Use Scenario: Sequenced 1.0V core and 1.8V auxiliary rails for Xilinx Versal ACAP with tight voltage accuracy and soft-start control. IC Role / Device Role / Timing Role: Dual-channel controller with independent TK/SS pins enabling precise voltage ramp tracking between rails. Use Value: Coordinated startup prevents FPGA configuration faults; OPTI-LOOP® maintains stability despite large ceramic + polymer cap mix. |
Use Scenario: 24V-to-5V/3.3V dual-output supply for isolated I/O modules requiring robustness against 40V load-dump transients. IC Role / Device Role / Timing Role: Industrial-grade controller with 38V absolute max VIN and integrated UVLO hysteresis (0.55V). Use Value: Wide input range eliminates need for front-end TVS/clamping; PGOOD co-bonding simplifies system fault monitoring. |
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 |
|---|---|---|---|
| MP2950GQ-0000-Z (Monolithic Power) | Integrated MOSFETs (40V/30A), fixed 500kHz freq, no VID pins, single PGOOD | Lower component count but limited to ≤12V output; no programmable current limit or phase sync | Choose for space-constrained, medium-current (<10A/rail) designs where integration outweighs flexibility |
| ISL95836IRZ (Renesas) | 3-phase capable, Intel VR12.5 compliant, SMBus interface, no ILIM pin, TSSOP-40 only | Targeted at CPU VRMs with digital telemetry; lacks analog VID strapping and QFN package option | Choose when digital PMBus control and Intel spec compliance are required over analog simplicity |
Compared with MP2950GQ-0000-Z and ISL95836IRZ, the LTC3865EUH#TRPBF offers unmatched analog configurability (VID, ILIM, FREQ, MODE/PLLIN), dual independent soft-start, and QFN thermal performance - making it optimal for custom high-current, high-reliability analog power designs.
Availability
LTC3865EUH#TRPBF is available at Aetrix Electronics and suitable for server VRMs, telecom intermediate bus converters, and FPGA power management units requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.
Supply support for LTC3865EUH#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 power portfolio with rigorous automotive and industrial qualification standards.
The LTC3865EUH#TRPBF belongs to Linear's flagship synchronous buck controller family, designed specifically for high-efficiency, high-current, multi-phase DC/DC conversion in datacenter, networking, and industrial equipment.
FAQ
What is the maximum supported switching frequency for the LTC3865EUH#TRPBF?
The LTC3865EUH#TRPBF supports a phase-lockable switching frequency range from 250kHz to 770kHz. At RFREQ = 0Ω, minimum frequency is 250kHz (typ); at RFREQ ≥ 325kΩ, maximum frequency reaches 770kHz (typ). This range allows optimization of magnetics size, efficiency, and EMI filtering for each application.
How does the ILIM pin affect current limiting on the LTC3865EUH#TRPBF?
The ILIM pin on the LTC3865EUH#TRPBF configures the maximum current sense threshold per channel: tying ILIM to GND sets 24mV, floating sets 44mV, and tying to INTVCC sets 68mV (E-grade). This directly scales the peak inductor current trip point without changing external sense components, enabling flexible OCP tuning.
Can the LTC3865EUH#TRPBF operate with only one channel enabled?
Yes, the LTC3865EUH#TRPBF supports independent channel control. Pulling RUN1 low disables Channel 1 while Channel 2 remains active; pulling RUN2 low disables Channel 2. Both channels can be operated simultaneously, independently, or in master-slave tracking configuration using TK/SS pins.
What is the purpose of the MODE/PLLIN pin on the LTC3865EUH#TRPBF?
The MODE/PLLIN pin on the LTC3865EUH#TRPBF serves dual functions: selecting light-load operation mode (Burst Mode® when floating, pulse-skipping when tied to INTVCC, forced continuous when grounded) and accepting an external clock for oscillator synchronization - enabling deterministic EMI reduction in noise-sensitive systems.
Does the LTC3865EUH#TRPBF require external bootstrap diodes?
No, the LTC3865EUH#TRPBF does not require external bootstrap diodes. Its internal charge pump architecture automatically recharges the bootstrap capacitors during normal operation. However, during dropout conditions (VIN ≈ VOUT), the internal dropout detector forces periodic top-FET off-time to ensure CB recharge - eliminating need for external diodes.
LTC3865EUH#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 32-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 ~ 770kHz
- Duty Cycle (Max):
- 95%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Current Limit, Enable, Frequency Control, Power Good, Soft Start, Tracking
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-QFN (5x5)
LTC3865EUH#TRPBF FAQ
1.How can I place an order for LTC3865EUH#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3865EUH#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 LTC3865EUH#TRPBF reliable?
The price and inventory of LTC3865EUH#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3865EUH#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3865EUH#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3865EUH#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3865EUH#TRPBF?
LTC3865EUH#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3865EUH#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 LTC3865EUH#TRPBF?
For technical support, including LTC3865EUH#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3865EUH#TRPBF requirements.
6.How does Aetrix verify that LTC3865EUH#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3865EUH#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 LTC3865EUH#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3865EUH#TRPBF?
All LTC3865EUH#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3865EUH#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 LTC3865EUH#TRPBF part is unused and in its original packaging.
Return procedure for LTC3865EUH#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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