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Analog Devices Inc. LTC3865IUH#TRPBF
- Part No.:
- LTC3865IUH#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 32-WFQFN Exposed Pad
- Datasheet:
-
LTC3865IUH#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 32QFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,754
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Product details
Overview
LTC3865IUH#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 OPTI-LOOP® compensation for stable transient response across wide output capacitance/ESR variations. Used in high-density server VRMs and telecom power distribution systems.
For engineers reviewing the LTC3865IUH#TRPBF datasheet, LTC3865IUH#TRPBF pinout, LTC3865IUH#TRPBF application, or LTC3865IUH#TRPBF equivalent, key selection criteria include dual-channel 180° phased operation, pin-selectable VID output programming (0.6V–5V), RSENSE/DCR current sensing, adjustable 250kHz–770kHz switching frequency, and independent track/soft-start control per channel.
Technical Context
The LTC3865IUH#TRPBF implements constant-frequency current-mode control with two independent error amplifiers (EA), transconductance gm = 2.2 mmho, and ITH pins that set peak inductor current via voltage-controlled threshold. Each channel features dedicated SENSE+/– inputs, VOSENSE feedback nodes, and programmable current foldback via ILIM pin configuration (GND/FLOAT/INTVCC).
Its phase-locked oscillator supports synchronization via MODE/PLLIN pin (accepting external clock) and frequency setting via FREQ pin (7.5μA sink current into resistor). The IC integrates dual N-channel gate drivers with TG/BG pull-up/down resistances of 2.6Ω/1.5Ω and 3Ω/1.4Ω respectively, plus internal 5V INTVCC regulator (4.8V–5.2V) with 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 pre-regulation. |
| Switching Frequency | 250kHz to 770kHz - adjustable via external resistor on FREQ pin; enables optimization of size vs. efficiency. |
| Output Voltage Range | 0.6V to 5.0V - programmed via 2-pin VID strapping (9 discrete settings) or external resistive dividers. |
| Current Sensing | RSENSE or DCR - selectable via layout; supports low-loss inductor-based sensing or precision shunt-based sensing. |
| Efficiency | Up to 95% - achieved through synchronous N-MOSFET drive, low driver RDS(ON), and phase interleaving reducing input/output ripple. |
| Operating Temp | –40°C to +125°C - fully specified I-grade performance over full junction temperature range. |
| Package | 32-pin 5mm × 5mm QFN - thermally enhanced exposed pad (SGND) for low θJA = 34°C/W. |
Pinout & Package
Package: 32-lead (5mm × 5mm) plastic QFN with exposed thermal pad (Pin 33 = SGND), RoHS-compliant, moisture sensitivity level 3.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VOSENSE1, VOSENSE2 (Pins 1, 8) | Error amplifier feedback input | Accepts remote-sensed output voltage or external divider signal; sets regulation point for each channel. |
| TK/SS1, TK/SS2 (Pins 2, 7) | Soft-start/tracking control | Internal 1.3μA current charges external capacitor to ramp output voltage; supports master-slave tracking. |
| ITH1, ITH2 (Pins 3, 6) | Error amplifier output / current threshold | Voltage sets peak inductor current; direct interface to compensation network and current limit control. |
| VID11, VID12, VID21, VID22 (Pins 4, 5, 12, 28) | Output voltage programming | Binary-coded strapping pins (GND/FLOAT/INTVCC) select one of nine preset VOUT values per channel. |
| ILIM (Pin 13) | Current sense threshold select | Configures max sense voltage (22–84mV) for current foldback during short-circuit conditions. |
| PGOOD (Pin 14) | Power-good indicator | Open-drain output asserted low if either channel deviates >±10% from target for >100μs. |
| MODE/PLLIN (Pin 27) | Mode selection / sync input | Selects Burst Mode®, pulse-skipping, or forced continuous mode; accepts external clock for phase lock. |
| FREQ (Pin 29) | Oscillator frequency set | 7.5μA sink current into resistor sets nominal frequency (250–770kHz); enables precise timing control. |
| RUN1, RUN2 (Pins 30, 11) | Channel enable/disable | 1.22V threshold with 80mV hysteresis; allows independent startup/shutdown of each controller. |
| TG1, TG2 / BG1, BG2 (Pins 25,16 / 23,19) | N-MOSFET gate drivers | High-side (TG) and low-side (BG) drivers with 2.6Ω/1.5Ω and 3Ω/1.4Ω RON; support fast switching with anti-shoot-through logic. |
Key Features
| Feature | Design Value |
|---|---|
| Dual 180° phased controllers | Reduces input/output RMS current by ~30%, cuts EMI peaks, and lowers capacitor stress in multi-rail systems. |
| OPTI-LOOP® compensation | Enables stable loop response across ±50% variation in output capacitance and ESR without redesigning compensation network. |
| Independent track/soft-start | Allows staggered startup sequencing between rails (e.g., core before I/O) or synchronized ramping using resistor divider coupling. |
| Adjustable current limit | Three ILIM configurations (GND/FLOAT/INTVCC) set sense threshold from 22mV to 84mV - matches diverse MOSFET RDS(ON) or sense resistor values. |
| Output OV protection | Monitors VOSENSE directly; triggers PGOOD deassertion and disables top MOSFET if output exceeds +12.5% or falls below –12.5%. |
| Phase-lockable oscillator | Accepts external clock up to 1MHz on MODE/PLLIN; enables synchronization to system clock or other regulators to eliminate beat frequencies. |
Applications
| Server VRM Core Power | Telecom Intermediate Bus Converter |
|---|---|
Use Scenario: Dual-output 1.5V/15A CPU core and 1.2V/15A memory rail in 1U rack server with strict thermal envelope. IC Role / Device Role / Timing Role: Dual-phase synchronous buck controller managing interleaved switching, current sharing, and coordinated soft-start. Use Value: 180° phase shift reduces input ripple current by 70%, enabling smaller bulk capacitors and lower conduction losses in PCB traces. |
Use Scenario: 48V-to-12V intermediate bus conversion feeding multiple downstream POL converters in wireless base station. IC Role / Device Role / Timing Role: High-efficiency primary controller with wide VIN range and robust fault protection for unregulated telecom input. Use Value: 95% peak efficiency at full load and Burst Mode® operation extend battery backup time during brownouts. |
| Industrial PLC Power Supply | Network Switch ASIC Power |
Use Scenario: Redundant 3.3V/10A and 5V/8A supplies powering FPGA, I/O, and communication interfaces in harsh factory environment. IC Role / Device Role / Timing Role: Dual-channel controller with independent RUN pins enabling hot-swap sequencing and graceful shutdown. Use Value: –40°C to +125°C guaranteed operation ensures reliability in uncooled enclosures; PGOOD monitoring enables system-level fault logging. |
Use Scenario: Multi-rail power for 10G Ethernet switch ASIC requiring tightly regulated 0.85V core, 1.2V I/O, and 3.3V auxiliary rails. IC Role / Device Role / Timing Role: Precision VID-programmed controller delivering <±0.5% output accuracy with fast transient response. Use Value: OPTI-LOOP® compensation maintains stability with ceramic-only output caps, eliminating electrolytic bulk capacitors and improving MTBF. |
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-Z (Monolithic Power) | Integrated power stage (MOSFETs + controller); fixed 500kHz frequency; no VID programming; single PGOOD. | Lower BOM count but less flexible output voltage tuning and thermal management than discrete-FET solution. | Choose MP2950GQ-Z for space-constrained designs where integration outweighs configurability needs. |
| ISL95836IRZ (Renesas) | Supports 3-phase operation; includes digital PMBus interface; higher quiescent current (12mA vs. 5mA); TSSOP-40 package only. | Required for systems needing telemetry, dynamic voltage scaling, or >2-phase interleaving beyond LTC3865IUH#TRPBF's capability. | Choose ISL95836IRZ when digital control, telemetry, or 3-phase scalability is mandatory. |
Compared with MP2950GQ-Z and ISL95836IRZ, the LTC3865IUH#TRPBF offers unmatched analog configurability - including pin-strapped VID, independent channel control, and RSENSE/DCR sensing - making it optimal for high-reliability, thermally demanding, or cost-sensitive discrete-FET power designs.
Availability
LTC3865IUH#TRPBF is available at Aetrix Electronics and suitable for server VRMs, telecom power distribution systems, and industrial PLC power supplies requiring stable component supply, long-term lifecycle support, and guaranteed I-grade temperature performance.
Supply support for LTC3865IUH#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 legacy of high-performance analog and power management ICs with rigorous automotive- and industrial-grade qualification.
The LTC3865IUH#TRPBF belongs to Linear's high-efficiency synchronous controller product line, designed specifically for high-current, multi-rail DC/DC conversion in datacenter, telecom, and industrial infrastructure where thermal density, transient response, and long-term reliability are critical.
FAQ
What is the maximum supported switching frequency for the LTC3865IUH#TRPBF?
The LTC3865IUH#TRPBF supports a phase-lockable fixed-frequency range from 250kHz to 770kHz. Frequency is set by an external resistor connected to the FREQ pin, which sinks a precise 7.5μA current. At RFREQ = 0Ω, minimum frequency is 250kHz; at RFREQ ≥ 325kΩ, maximum frequency reaches 770kHz. This range balances efficiency, size, and EMI requirements in high-density power designs.
How does the ILIM pin affect current limiting on the LTC3865IUH#TRPBF?
The ILIM pin on the LTC3865IUH#TRPBF selects the maximum current sense threshold for both channels: tying ILIM to GND sets VSENSE(MAX) = 22mV (I-grade), FLOAT yields 50mV, and INTVCC configures 84mV. This directly determines the peak inductor current trip point and enables current foldback during overload or short-circuit events - protecting external MOSFETs without requiring external circuitry.
Can the LTC3865IUH#TRPBF operate with only one channel enabled?
Yes, the LTC3865IUH#TRPBF supports independent channel control via RUN1 and RUN2 pins. Pulling RUN1 low disables Channel 1 while leaving Channel 2 fully operational, and vice versa. Both channels can be disabled simultaneously for complete system shutdown. This enables flexible power sequencing, dynamic rail disabling, and fault isolation in multi-output systems.
What is the purpose of the MODE/PLLIN pin on the LTC3865IUH#TRPBF?
The MODE/PLLIN pin on the LTC3865IUH#TRPBF serves dual functions: selecting operating mode (Burst Mode®, pulse-skipping, or forced continuous conduction) and accepting an external synchronization clock. Tying it to SGND forces continuous mode; to INTVCC enables pulse-skipping; floating enables Burst Mode®. Applying an external clock synchronizes both channels' oscillators, eliminating beat frequencies in multi-regulator systems.
Does the LTC3865IUH#TRPBF support DCR current sensing?
Yes, the LTC3865IUH#TRPBF fully supports DCR current sensing via dedicated SENSE1+/– and SENSE2+/– pins. It includes slope compensation and reverse current detection (IREV) to prevent negative inductor current during light-load Burst Mode® operation. DCR sensing eliminates power loss from shunt resistors and improves efficiency in high-current applications like server VRMs.
LTC3865IUH#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)
LTC3865IUH#TRPBF FAQ
1.How can I place an order for LTC3865IUH#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3865IUH#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 LTC3865IUH#TRPBF reliable?
The price and inventory of LTC3865IUH#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3865IUH#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3865IUH#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3865IUH#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3865IUH#TRPBF?
LTC3865IUH#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3865IUH#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 LTC3865IUH#TRPBF?
For technical support, including LTC3865IUH#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3865IUH#TRPBF requirements.
6.How does Aetrix verify that LTC3865IUH#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3865IUH#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 LTC3865IUH#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3865IUH#TRPBF?
All LTC3865IUH#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3865IUH#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 LTC3865IUH#TRPBF part is unused and in its original packaging.
Return procedure for LTC3865IUH#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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