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Analog Devices Inc. LTC3865EUH-1#TRPBF
- Part No.:
- LTC3865EUH-1#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 32-WFQFN Exposed Pad
- Datasheet:
-
LTC3865EUH-1#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 32QFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,636
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Product details
Overview
LTC3865EUH-1#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-1#TRPBF datasheet, LTC3865EUH-1#TRPBF pinout, LTC3865EUH-1#TRPBF application, or LTC3865EUH-1#TRPBF equivalent, key selection criteria include its dual-channel phase-lockable 250kHz–770kHz operation, independent track/soft-start control, OPTI-LOOP® compensation, RSENSE/DCR current sensing, and output overvoltage protection with reverse current limiting.
Technical Context
The LTC3865EUH-1#TRPBF implements constant-frequency current-mode control with two independent 180° out-of-phase channels. Each channel features a transconductance error amplifier (gm = 2.2 mmho), programmable current limit via ILIM pin, and selectable operating mode (Burst Mode®, pulse-skipping, or forced continuous) via MODE/PLLIN.
It supports dual N-channel synchronous drive with dedicated TG/BG outputs, integrated 5V INTVCC regulator (4.8V–5.2V), EXTVCC switchover at 4.7V, and precision 0.6V reference with ±0.5% initial accuracy. The device uses OPTI-LOOP® compensation for stable transient response across wide output capacitance and ESR ranges.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5V to 38V - supports wide industrial and telecom input rails including 12V, 24V, and 28V systems. |
| Output Voltage Range | 0.6V to 5.0V - set via 2-pin VID strapping (9 discrete levels) or external resistive dividers. |
| Switching Frequency | 250kHz to 770kHz - adjustable via FREQ pin current (7.5μA) and external resistor; phase-lockable to external clock. |
| Max Duty Cycle | 95% - enables high step-down ratios (e.g., 24V→1.2V) while maintaining minimum on-time margin. |
| Current Sense Threshold | Default 50mV (LTC3865-1 variant) - fixed maximum sense voltage simplifies current limit calibration vs. adjustable versions. |
| Efficiency | Up to 95% - achieved via low-RDS(on) gate drivers (TG RUP = 2.6Ω, BG RDOWN = 1.4Ω) and optimized dead-time control. |
| Operating Temp | –40°C to +125°C - qualified for extended industrial and base station environments. |
Pinout & Package
Package: 32-lead (5mm × 5mm) plastic QFN with exposed SGND pad (Pin 33), θJA = 34°C/W. Requires soldering of exposed pad to PCB for thermal and signal integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VOSENSE1 / VOSENSE2 | Error amplifier feedback input | Accepts remote-sensed output voltage or external divider; enables accurate regulation under load transient conditions. |
| TK/SS1 / TK/SS2 | Soft-start & tracking control | Internal 1.3μA current charges external capacitor for linear VOUT ramp; supports master-slave voltage sequencing. |
| ITH1 / ITH2 | Error amplifier output & current threshold | Directly sets peak inductor current; voltage range 0–2.7V maps to full current limit scale. |
| VID11/VID12/VID21/VID22 | Output voltage programming inputs | Binary-coded strapping pins selecting one of nine preset VOUT values (0.6V–5.0V) without external resistors. |
| MODE/PLLIN | Operating mode select & sync input | Configures Burst Mode® (float), pulse-skip (INTVCC), or forced continuous (SGND); accepts external clock for synchronization. |
| PGOOD1 / PGOOD2 | Independent power-good indicators | Open-drain outputs asserting low when respective VOUT deviates >±10%; includes 100μs blanking time after startup. |
| TG1/TG2, BG1/BG2 | Top/bottom gate drivers | Drive N-MOSFET gates with 2.6Ω pull-up / 1.5Ω pull-down strength; support bootstrap-based high-side drive. |
| SENSE1+/SENSE1−, SENSE2+/SENSE2− | Differential current sense inputs | Accept DCR or RSENSE signals; reject common-mode noise up to 38V common-mode range. |
Key Features
| Feature | Design Value |
|---|---|
| Dual 180° phased controllers | Reduces input/output ripple current by ~70% vs. single-phase, enabling smaller bulk capacitors and lower EMI. |
| OPTI-LOOP® compensation | Allows stable loop response across 10× variation in output capacitance and ESR-critical for multi-capacitor ceramic + polymer designs. |
| Independent track/soft-start | Enables precise power sequencing (e.g., core before I/O) and eliminates inrush current damage during cold start. |
| Output OV protection with reverse current limit | Prevents destructive shoot-through during load dump or hot-swap events by disabling bottom FET before zero-crossing. |
| RSENSE or DCR current sensing | Supports both discrete shunt resistors (high accuracy) and copper trace DCR (cost-optimized, no extra component). |
Applications
| Server VRM | Telecom Power Shelf |
|---|---|
Use Scenario: Dual-output CPU/GPU core power delivery in 1U rack servers requiring tight voltage regulation and fast transient response. IC Role / Device Role / Timing Role: Dual-phase synchronous buck controller managing 1.5V/15A and 1.2V/15A rails with interleaved switching to reduce input ripple. Use Value: 95% peak efficiency minimizes thermal load in constrained airflow environments; 180° phasing cuts input capacitor RMS current by 70%. | Use Scenario: Distributed 12V-to-3.3V/5V conversion in carrier-grade power shelves with strict hold-up and redundancy requirements. IC Role / Device Role / Timing Role: Primary DC/DC controller for intermediate bus converters, supporting burst-mode operation during standby to meet <1W idle power targets. Use Value: Burst Mode® reduces light-load quiescent current to 30μA per channel, extending system standby time without compromising startup speed. |
| Industrial PLC CPU Board | High-Density FPGA Power |
Use Scenario: Multi-rail power for ARM Cortex-A series processors and real-time Ethernet interfaces in harsh industrial environments. IC Role / Device Role / Timing Role: Dual-channel controller delivering 1.1V core and 1.8V I/O supplies with independent soft-start and power-good monitoring. Use Value: –40°C to +125°C operation ensures reliability in uncooled enclosures; independent RUN1/RUN2 pins enable firmware-controlled rail sequencing. | Use Scenario: Compact, high-current power for Xilinx Kintex UltraScale+ FPGAs requiring tightly regulated 0.85V core and 1.2V auxiliary rails. IC Role / Device Role / Timing Role: Phase-interleaved controller implementing precise voltage tracking between core and auxiliary supplies during configuration. Use Value: TK/SS1–TK/SS2 tracking capability ensures monotonic startup without FPGA configuration errors due to supply sequencing violations. |
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 |
|---|---|---|---|
| ISL95812IRZ-T | Single-chip dual-phase controller with integrated MOSFET drivers only; no VID strapping-requires external DAC or resistor network for VOUT setting. | Targeted at notebook CPU VRMs; lacks EXTVCC switchover and has narrower 4.5V–24V input range. | Select when board space is critical and integrated drivers suffice; avoid if 28V input or VID simplicity is required. |
| MP8765GL-Z | Monolithic dual-phase buck converter (integrated MOSFETs); fixed 500kHz frequency; no phase-lock or external sync capability. | Designed for consumer SSDs and embedded SoCs; max 12A per phase, no RSENSE/DCR flexibility. | Choose for cost-sensitive, low-complexity designs where 12A/channel and fixed frequency are acceptable. |
Compared with ISL95812IRZ-T and MP8765GL-Z, the LTC3865EUH-1#TRPBF offers wider input range (4.5V–38V), pin-strappable VID outputs, phase-lockable frequency, and flexible current sensing-making it optimal for industrial and telecom systems demanding configurability and ruggedness.
Availability
LTC3865EUH-1#TRPBF is available at Aetrix Electronics and suitable for server VRMs, telecom power shelves, and industrial PLC CPU boards requiring stable component supply, long-term lifecycle support, and guaranteed performance across –40°C to +125°C.
Supply support for LTC3865EUH-1#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. Linear's legacy design rigor ensures robustness in mission-critical power applications.
The LTC3865EUH-1#TRPBF belongs to Linear's high-efficiency synchronous controller family, engineered for high-density, multi-phase DC/DC conversion in datacenter, telecom, and industrial infrastructure where thermal management and transient response are paramount.
FAQ
What is the key functional difference between LTC3865EUH-1#TRPBF and the standard LTC3865EUH#TRPBF?
The LTC3865EUH-1#TRPBF fixes the maximum current sense threshold at 50mV (per Note 8), eliminating ILIM pin dependency for current limit setting. In contrast, the standard LTC3865EUH#TRPBF allows adjustment of this threshold (24mV–82mV) via the ILIM pin tied to GND/FLOAT/INTVCC. This simplifies design for applications requiring consistent current foldback behavior without external configuration.
Does LTC3865EUH-1#TRPBF support output voltage tracking between its two channels?
Yes, LTC3865EUH-1#TRPBF supports precise coincident tracking using the TK/SS1 and TK/SS2 pins. When configured as master-slave, an external resistor divider from the master's output to SGND applied to the slave's TK/SS pin replicates the master's soft-start ramp. This ensures monotonic, synchronized startup-critical for FPGA and processor core/I/O rail sequencing.
What is the recommended layout practice for the exposed pad (Pin 33) on the LTC3865EUH-1#TRPBF QFN package?
The exposed pad (Pin 33) of the LTC3865EUH-1#TRPBF must be soldered to a dedicated SGND copper area on the PCB. This pad serves as the primary signal ground reference and thermal path. It should connect to the main PGND plane at a single point near the IC to prevent ground loops, and be thermally isolated from high-current PGND traces to avoid noise coupling into sensitive analog circuitry.
Can LTC3865EUH-1#TRPBF operate with only one channel active while the other is disabled?
Yes, LTC3865EUH-1#TRPBF supports independent channel control via RUN1 and RUN2 pins. Pulling RUN1 low disables Channel 1 (including TG1/BG1, BOOST1, SW1), while Channel 2 remains fully operational. This enables dynamic power scaling-for example, disabling the 1.2V rail during low-power states while maintaining 1.5V core supply for background processing.
How does the MODE/PLLIN pin configure Burst Mode® operation on LTC3865EUH-1#TRPBF?
On LTC3865EUH-1#TRPBF, leaving the MODE/PLLIN pin floating enables Burst Mode® operation-reducing light-load quiescent current to 30μA per channel. In this mode, the controller discontinuously pulses the top FET to maintain regulation, suppressing switching losses. The internal sleep signal activates when ITH drops below 0.5V, turning off both FETs until output droop triggers resumption.
LTC3865EUH-1#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-1#TRPBF FAQ
1.How can I place an order for LTC3865EUH-1#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3865EUH-1#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-1#TRPBF reliable?
The price and inventory of LTC3865EUH-1#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-1#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3865EUH-1#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3865EUH-1#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3865EUH-1#TRPBF?
LTC3865EUH-1#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3865EUH-1#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-1#TRPBF?
For technical support, including LTC3865EUH-1#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3865EUH-1#TRPBF requirements.
6.How does Aetrix verify that LTC3865EUH-1#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3865EUH-1#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-1#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3865EUH-1#TRPBF?
All LTC3865EUH-1#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3865EUH-1#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-1#TRPBF part is unused and in its original packaging.
Return procedure for LTC3865EUH-1#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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