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Analog Devices Inc. LTC3731HUH#TRPBF
- Part No.:
- LTC3731HUH#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 32-WFQFN Exposed Pad
- Datasheet:
-
LTC3731HUH#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 32QFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,153
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Product details
Overview
LTC3731HUH#TRPBF from Analog Devices (formerly Linear Technology) is a 3-phase, synchronous buck switching regulator controller designed for high-current DC/DC conversion in industrial and automotive power supplies. It drives external N-channel MOSFETs with 120° phase separation up to 680kHz per phase, supports 0.6V–6V output voltage, delivers ±5% current matching across phases, and operates over –40°C to 140°C junction temperature.
For engineers reviewing the LTC3731HUH#TRPBF datasheet, LTC3731HUH#TRPBF pinout, LTC3731HUH#TRPBF application, or LTC3731HUH#TRPBF equivalent, this page provides verified technical context, validated pin functions, confirmed thermal and frequency specifications, and real-world application mappings - all grounded in the official LTC3731H datasheet and package documentation.
Technical Context
The LTC3731HUH#TRPBF implements a fixed-frequency, current-mode polyphase architecture with three independent PWM channels synchronized via internal PLL or external clock. Each channel features dedicated differential current sense inputs (SENSE1± through SENSE3±), floating top-gate drivers (TG1–TG3), and bootstrapped high-side drive capability up to 38V BOOST–SW differential.
It integrates OPTI-LOOP® compensation for minimized output capacitance, selectable light-load operation (Burst Mode®, Stage Shedding™, or forced continuous), and precision 0.6V reference with ±2% accuracy over full temperature range. Protection includes short-circuit foldback, overvoltage soft latch, undervoltage lockout (adjustable via UVADJ), and thermal shutdown at >140°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Topology | 3-phase synchronous buck controller - enables tripled effective switching frequency and reduced input/output RMS current stress. |
| Max Switching Frequency | 680kHz per phase - allows smaller magnetics and faster transient response while maintaining thermal efficiency. |
| Output Voltage Range | 0.6V to 6V - set by external resistor divider on EAIN; supports core logic, FPGA, and ASIC rail requirements. |
| Current Matching Accuracy | ±5% between phases - ensures balanced thermal loading and enables parallel inductor sizing without derating. |
| Junction Temperature Range | –40°C to +140°C - qualified for under-hood automotive and high-ambient industrial environments. |
| Reference Voltage Accuracy | ±2% over full temperature range - guarantees stable regulation without external trimming in harsh thermal conditions. |
| Phase Separation | 120° per phase - minimizes input capacitor ripple current and improves system-level power delivery stability. |
| Light-Load Modes | Burst Mode®, Stage Shedding™, or forced continuous - selectable via FCB pin to optimize efficiency vs. noise trade-offs. |
Pinout & Package
The LTC3731HUH#TRPBF is housed in a 32-lead (5mm × 5mm) plastic QFN package with exposed thermal pad (Pin 33 = SGND). This thermally enhanced package achieves θJA = 34°C/W and θJC = 3°C/W, enabling high-power density designs without heatsinks in constrained layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| TG1–TG3 | Top gate drivers | Floating high-current outputs driving N-channel MOSFET gates; require bootstrap capacitors tied between BOOSTx and SWx. |
| BG1–BG3 | Bottom gate drivers | Ground-referenced drivers for synchronous rectification; swing from PGND to VCC (or VDR). |
| SENSE1±–SENSE3± | Differential current sense inputs | Measure voltage drop across external sense resistors; enable per-phase current limiting and matching. |
| EAIN | Error amplifier input | Compares feedback voltage to internal 0.6V reference; sets output regulation point and loop stability. |
| ITH | Error amplifier output / compensation node | Controls peak current threshold for all three phases; used for loop compensation and current limit programming. |
| FCB | Mode selection control | Selects Burst Mode® (float), Stage Shedding™ (tied to VCC), or forced continuous (grounded). |
| PLLIN / PLLFLTR | Frequency synchronization interface | Accepts external sync signal (PLLIN) or DC voltage (PLLFLTR) to lock or set oscillator from 225kHz to 680kHz. |
| PGOOD | Open-drain power-good indicator | Asserts low when output deviates >±10% for ≥100µs; enables system sequencing and fault reporting. |
| RUN/SS | Soft-start and short-circuit timer | Capacitor-based ramp controls startup inrush and latches off during sustained overcurrent (e.g., <70% VOUT). |
| UVADJ | Adjustable undervoltage lockout | Comparator input referenced to 1.2V; disables regulators when applied voltage falls below threshold. |
| CLKOUT | Synchronization output | Provides phase-aligned clock for cascading additional controllers in 6- or 12-phase systems. |
| PHASMD | Phase shift select | Configures CLKOUT-to-TG1 phase offset as 30° (low) or 60° (high); critical for multi-controller timing alignment. |
Key Features
| Feature | Design Value |
|---|---|
| PolyPhase® 3-phase architecture | Reduces input/output capacitor RMS current by ~58% versus single-phase, lowering thermal stress and component count. |
| OPTI-LOOP® compensation | Minimizes required output capacitance by optimizing loop bandwidth and phase margin without external type-II/III networks. |
| ±5% inter-phase current matching | Enables uniform thermal distribution across MOSFETs and inductors, eliminating need for oversized components or derating. |
| 140°C junction-rated operation | Supports direct placement near hot components (e.g., CPUs, GPUs) without thermal throttling or derating in sealed enclosures. |
| Selectably optimized light-load efficiency | Stage Shedding™ eliminates gate charge losses of inactive phases; Burst Mode® reduces switching loss at ultra-light loads. |
| Integrated protection suite | Includes foldback current limiting, overvoltage soft latch, adjustable UVLO, and programmable short-circuit timeout. |
Applications
| High-Current CPU/GPU Core Power | Automotive ADAS Domain Controller Supply |
|---|---|
|
Use Scenario: Delivering 55A at 1.35V to advanced microprocessors in server or AI accelerator boards with strict transient response and thermal constraints. IC Role / Device Role / Timing Role: 3-phase synchronous buck controller managing parallel power stages with precise current balancing and fast load-step recovery. Use Value: Achieves >90% efficiency at full load while reducing input ripple current by 90% versus single-phase, easing EMI filter design and capacitor lifetime. |
Use Scenario: Providing robust, high-reliability 3.3V/5V rails for radar processing units and camera SoCs in vehicles operating from –40°C to +125°C ambient. IC Role / Device Role / Timing Role: High-temperature-rated controller ensuring stable regulation and fault immunity under engine-bay thermal cycling and load dump conditions. Use Value: 140°C junction rating and ±2% VREF accuracy eliminate need for external calibration or thermal derating in safety-critical domains. |
| Industrial PLC I/O Module Power | Telecom Baseband Unit (BBU) Intermediate Bus |
|
Use Scenario: Generating isolated 12V intermediate bus from 24V/48V field supply in programmable logic controllers requiring long-term reliability and wide-temp operation. IC Role / Device Role / Timing Role: Primary controller for multiphase buck converter feeding downstream isolated DC/DC modules; manages phase shedding during standby. Use Value: Stage Shedding™ extends light-load efficiency to <1% of full scale, reducing standby power and heat buildup in fanless enclosures. |
Use Scenario: Converting 48V backplane to 12V/5V intermediate buses in 5G baseband units where board space, thermal density, and EMI are tightly constrained. IC Role / Device Role / Timing Role: High-frequency (680kHz) 3-phase controller enabling compact magnetics and low-profile ceramic output capacitors. Use Value: 680kHz per-phase operation reduces inductor size by >40% vs. 300kHz alternatives while maintaining >92% efficiency at 40A. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 3-phase synchronous buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MP2940AGQ-Z | 40V max VIN, 125°C rated, integrated MOSFET drivers only (no external FET support); no PLL sync or PHASMD pin. | Targeted at lower-power (<30A), cost-sensitive telecom modules; lacks 140°C rating and phase extension capability. | Choose MP2940AGQ-Z only if integrated drivers suffice and extended temperature operation is not required. |
| ISL95836IRZ | Intel VR12.5/VR13 compliant, supports DVID; 125°C rated; requires external op-amp for current sensing; no Stage Shedding™ mode. | Designed specifically for client CPU VRMs; lacks automotive qualification and flexible light-load mode selection. | Prefer ISL95836IRZ only for Intel platform-specific designs requiring dynamic VID and telemetry interfaces. |
Compared with MP2940AGQ-Z and ISL95836IRZ, the LTC3731HUH#TRPBF uniquely combines 140°C operation, true 3-phase current matching, PLL-based synchronization for scalable multi-phase systems, and three distinct light-load modes - making it the only option qualified for high-reliability automotive and industrial applications demanding both thermal resilience and architectural flexibility.
Availability
LTC3731HUH#TRPBF is available at Aetrix Electronics and suitable for high-current CPU/GPU power delivery, automotive ADAS domain controllers, and industrial PLC I/O modules requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LTC3731HUH#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 full product support, datasheet archives, and application engineering resources for all Linear ICs including the LTC3731H family.
The LTC3731H series was engineered specifically for high-efficiency, high-current, multi-phase DC/DC conversion in thermally demanding environments - targeting automotive, industrial, and computing power systems where reliability, precision, and thermal headroom are non-negotiable.
FAQ
What is the maximum operating junction temperature of the LTC3731HUH#TRPBF?
The LTC3731HUH#TRPBF is fully specified and guaranteed over a junction temperature range of –40°C to +140°C. Its 5mm × 5mm QFN package with exposed thermal pad achieves θJA = 34°C/W, enabling reliable operation in under-hood automotive and high-ambient industrial applications without active cooling. The device includes overtemperature protection that activates above 140°C.
How does the LTC3731HUH#TRPBF achieve ±5% current matching between phases?
The LTC3731HUH#TRPBF achieves ±5% worst-case inter-phase current matching through matched internal current sense comparators, precision reference voltage (±2% over temperature), and symmetrical layout of SENSE+ and SENSE– paths within the die. This matching is validated across –40°C to +140°C and eliminates need for external calibration or individual phase trimming in production.
Can the LTC3731HUH#TRPBF be synchronized to an external clock source?
Yes - the LTC3731HUH#TRPBF supports external synchronization via its PLLIN pin, which accepts TTL/CMOS-compatible clock signals. The internal phase-locked loop aligns the rising edge of TG1 with the rising edge of the PLLIN signal. Alternatively, a DC voltage applied to PLLFLTR sets frequency from 225kHz to 680kHz, enabling precise system-level timing coordination.
What are the key differences between Burst Mode® and Stage Shedding™ operation on the LTC3731HUH#TRPBF?
Burst Mode® (FCB float) pulses full 3-phase operation followed by sleep intervals to minimize light-load switching loss, yielding highest efficiency but higher output ripple. Stage Shedding™ (FCB = VCC) disables two phases entirely below ~10% load, retaining constant-frequency operation with lower noise and better EMI profile - ideal for noise-sensitive analog or RF subsystems powered from the same rail.
Does the LTC3731HUH#TRPBF support adjustable undervoltage lockout?
Yes - the LTC3731HUH#TRPBF features an adjustable UVLO function via the UVADJ pin. An external resistor divider sets the turn-on threshold relative to the internal 1.2V reference. When UVADJ voltage falls below 1.2V, the controller disables all gate drivers and discharges the RUN/SS capacitor, providing precise input rail monitoring for brown-out protection in mission-critical systems.
LTC3731HUH#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- PolyPhase®
- 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:
- 3
- Output Phases:
- 3
- Voltage - Supply (Vcc/Vdd):
- 3.8V ~ 7V
- Frequency - Switching:
- 225kHz ~ 680kHz
- Duty Cycle (Max):
- 98.5%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Enable, Phase Control, Power Good, Soft Start
- Operating Temperature:
- -40°C ~ 140°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 32-QFN (5x5)
LTC3731HUH#TRPBF FAQ
1.How can I place an order for LTC3731HUH#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3731HUH#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 LTC3731HUH#TRPBF reliable?
The price and inventory of LTC3731HUH#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3731HUH#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3731HUH#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3731HUH#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3731HUH#TRPBF?
LTC3731HUH#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3731HUH#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 LTC3731HUH#TRPBF?
For technical support, including LTC3731HUH#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3731HUH#TRPBF requirements.
6.How does Aetrix verify that LTC3731HUH#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3731HUH#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 LTC3731HUH#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3731HUH#TRPBF?
All LTC3731HUH#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3731HUH#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 LTC3731HUH#TRPBF part is unused and in its original packaging.
Return procedure for LTC3731HUH#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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