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Analog Devices Inc. LT3481HDD#TRPBF
- Part No.:
- LT3481HDD#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-WFDFN Exposed Pad
- Datasheet:
-
LT3481HDD#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 2A 10DFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,186
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Product details
Overview
LT3481HDD#TRPBF from Analog Devices (formerly Linear Technology) is a high-voltage, current-mode synchronous step-down DC/DC regulator with integrated 0.18Ω NPN switch and boost Schottky diode. It operates from 3.6V to 34V input, delivers up to 2A output, supports adjustable switching frequency from 300kHz to 2.8MHz, and achieves 50μA quiescent current in Burst Mode for automotive battery regulation and industrial power supplies.
For engineers reviewing the LT3481HDD#TRPBF datasheet, LT3481HDD#TRPBF pinout, LT3481HDD#TRPBF application, or LT3481HDD#TRPBF equivalent, key selection criteria include its –40°C to 150°C guaranteed operating temperature range, 1.265V feedback reference, integrated boost diode, power good flag, and thermally enhanced 3mm × 3mm DFN package with exposed ground pad.
Technical Context
The LT3481HDD#TRPBF uses constant-frequency current-mode control with internal slope compensation and an active VC clamp for precise peak-current limiting. Its oscillator is resistor-programmable via the RT pin and supports synchronization in the 275kHz–475kHz range.
Operation includes low-ripple Burst Mode for light-load efficiency, soft-start via RUN/SS pin ramping, bias-current sourcing from VOUT (when >3V) to reduce VIN quiescent draw, and a dedicated open-collector PG flag asserting at 90% of regulated output voltage.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.6V to 34V operating; 36V absolute max - supports wide-range industrial and automotive inputs without external protection. |
| Output Current | Up to 2A continuous - sufficient for powering FPGAs, microcontrollers, and sensor subsystems from single-rail supplies. |
| Switching Frequency | 300kHz to 2.8MHz (RT-programmable) - enables compact magnetics and noise spectrum tailoring for EMI-sensitive applications. |
| Quiescent Current | 50μA at 12VIN→3.3VOUT in Burst Mode - extends battery life in always-on portable and telematics systems. |
| Feedback Reference | 1.265V ±1.2% - sets output voltage accuracy and stability across temperature for precision regulation. |
| Thermal Rating | –40°C to 150°C junction - qualified for under-hood automotive and high-ambient industrial environments. |
| Power Good Flag | Open-collector PG asserts when VFB reaches 90% of target - provides reliable system-level power sequencing and fault monitoring. |
Pinout & Package
LT3481HDD#TRPBF is housed in a 10-lead, 3mm × 3mm plastic DFN package with exposed thermal pad (Pin 11), rated θJA = 43°C/W. The exposed pad must be soldered to PCB ground for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BD (Pin 1) | Boost Diode Anode Connection | Connects external Schottky anode to enable boosted gate drive for full NPN saturation. |
| BOOST (Pin 2) | Boost Capacitor Node | Provides >VIN voltage to internal switch driver; max 56V rating limits external capacitor selection. |
| SW (Pin 3) | Switch Output Node | Drives inductor and catch diode; carries high di/dt; requires tight layout to minimize EMI and voltage spikes. |
| VIN (Pin 4) | Main Input Supply | Powers internal regulator and switch; bypass with ≥4.7μF ceramic close to pin for ripple suppression. |
| RUN/SS (Pin 5) | Enable & Soft-Start Control | Logic-high (>2.5V) enables operation; RC network here sets output voltage ramp rate during startup. |
| PG (Pin 6) | Power Good Output | Open-collector flag pulled high externally; valid only when VIN > 3.5V and RUN/SS is high. |
| BIAS (Pin 7) | Bias Supply Input | Accepts VOUT (≥3V) to reduce VIN quiescent draw - improves light-load efficiency significantly. |
| FB (Pin 8) | Feedback Input | Regulated to 1.265V; connects to resistor divider; 30nA bias current enables high-impedance networks. |
| VC (Pin 9) | Error Amplifier Output | Controls peak switch current; RC compensation network here stabilizes loop dynamics. |
| RT (Pin 10) | Frequency Set Resistor | Grounded resistor programs switching frequency; 8.66kΩ yields 2.8MHz per datasheet table. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Boost Schottky Diode | Eliminates external diode, reducing BOM count and board area while ensuring optimal timing for NPN saturation. |
| Low-Ripple Burst Mode Operation | Maintains output ripple <15mV at light loads - avoids audible noise and meets strict analog supply requirements. |
| Saturating Switch Design | 0.18Ω on-resistance at 2A ensures minimal conduction loss and thermal rise in high-current operation. |
| Programmable Soft-Start | RUN/SS pin accepts external RC to control output voltage ramp time - prevents inrush current and downstream reset glitches. |
| Thermally Enhanced DFN | 3mm × 3mm footprint with exposed GND pad delivers 43°C/W junction-to-ambient - enables 2A operation without heatsink in compact layouts. |
Applications
| Automotive Battery Regulation | Industrial Distributed Power |
|---|---|
Use Scenario: Regulating 12V/24V vehicle battery rails to 3.3V/5V for infotainment ECUs and ADAS sensors. IC Role / Device Role / Timing Role: Primary buck converter providing stable, low-noise supply with cold-crank immunity down to 3.6V. Use Value: –40°C to 150°C rating ensures reliability under hood; 36V abs-max withstands load-dump transients. | Use Scenario: Local point-of-load conversion in programmable logic controllers and motor drives with wide-input industrial supplies. IC Role / Device Role / Timing Role: High-efficiency, thermally robust DC/DC stage delivering 2A at 5V from 18–34V unregulated bus. Use Value: Integrated boost diode and 0.18Ω switch reduce component count and thermal stress in enclosed enclosures. |
| Portable Product Power | Wall Transformer Regulation |
Use Scenario: Powering handheld test equipment and portable medical devices from multi-cell Li-ion or 12V adapters. IC Role / Device Role / Timing Role: Main system regulator enabling long runtime via 50μA Burst Mode IQ and efficient light-load operation. Use Value: Adjustable frequency allows EMI optimization; soft-start prevents brownout during battery insertion. | Use Scenario: Replacing linear regulators in AC/DC wall adapters to improve efficiency and reduce heat in compact enclosures. IC Role / Device Role / Timing Role: High-input buck controller converting rectified 30–34V DC to 5V/3.3V with minimal external components. Use Value: 34V operating input and 36V transient tolerance eliminate need for pre-regulation stages. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3631EMSE#PBF | 40V max input, 1.5A output, 3mm × 4mm MSOP, no integrated boost diode | Lower current, higher input voltage, requires external bootstrap diode | Choose for 40V systems where 1.5A suffices and board space permits external diode. |
| MP2451DT-LF-Z | 36V max input, 0.6A output, 8-pin SOIC, no PG flag or BIAS pin | Lower cost, lower current, missing power-good signaling and bias-sourcing capability | Choose for cost-sensitive, non-safety-critical 0.6A applications without sequencing or ultra-low-IQ needs. |
Compared with LTC3631EMSE#PBF and MP2451DT-LF-Z, LT3481HDD#TRPBF uniquely combines 2A output, integrated boost diode, –40°C to 150°C operation, and 50μA Burst Mode IQ - making it optimal for thermally demanding, high-reliability automotive and industrial buck conversion where component count and light-load efficiency are critical.
Availability
LT3481HDD#TRPBF is available at Aetrix Electronics and suitable for automotive battery regulation, industrial distributed power, and portable product power requiring stable component supply across extended temperature ranges.
Supply support for LT3481HDD#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 power management portfolio with rigorous automotive and industrial qualification standards.
The LT3481 product line delivers high-voltage, high-efficiency buck regulation for harsh-environment applications where wide input range, thermal resilience, and low-light-load IQ are essential design requirements.
FAQ
What is the maximum guaranteed junction temperature for LT3481HDD#TRPBF?
The LT3481HDD#TRPBF is specified for operation from –40°C to 150°C junction temperature, with absolute maximum rating of 150°C. This H-grade variant is qualified for under-hood automotive and high-ambient industrial use cases where standard I-grade (–40°C to 125°C) parts would exceed thermal limits. Derating applies above 125°C per datasheet Note 2.
Does LT3481HDD#TRPBF require an external boost diode?
No, LT3481HDD#TRPBF integrates a boost Schottky diode on-die - Pin BD connects directly to the internal diode anode, eliminating the need for an external component. This reduces bill-of-materials count, PCB area, and layout complexity while ensuring optimal timing between BOOST capacitor charging and switch drive.
How does the BIAS pin improve efficiency in LT3481HDD#TRPBF?
The BIAS pin on LT3481HDD#TRPBF allows sourcing bias current from VOUT (when ≥3V) instead of VIN, reducing input quiescent current - especially beneficial in high VIN-to-VOUT step-down scenarios. In typical 12V→3.3V operation, this architecture lowers total IQ by up to 50%, directly extending battery life in portable applications.
What is the function of the RT pin on LT3481HDD#TRPBF?
RT pin on LT3481HDD#TRPBF sets the switching frequency by connecting an external resistor to ground. Values from 8.66kΩ (2.8MHz) to 187kΩ (300kHz) are supported per datasheet Figure 1. This resistor-programmable oscillator enables EMI optimization, inductor size reduction, and duty-cycle margin tuning for specific input-output voltage ratios.
Can LT3481HDD#TRPBF operate with input voltages above 34V?
Yes - LT3481HDD#TRPBF supports 36V absolute maximum input voltage. During normal regulation (no startup or overload), 36V transients are acceptable. However, during start-up or short-circuit conditions, input must remain ≤34V and satisfy the fSW-dependent equation in datasheet Section 9 to avoid violating minimum on-time constraints.
LT3481HDD#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 10-WFDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3.6V
- Voltage - Input (Max):
- 34V
- Voltage - Output (Min/Fixed):
- 1.265V
- Voltage - Output (Max):
- 20V
- Current - Output:
- 2A
- Frequency - Switching:
- 300kHz ~ 2.8MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-DFN (3x3)
LT3481HDD#TRPBF FAQ
1.How can I place an order for LT3481HDD#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3481HDD#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 LT3481HDD#TRPBF reliable?
The price and inventory of LT3481HDD#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3481HDD#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3481HDD#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3481HDD#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3481HDD#TRPBF?
LT3481HDD#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3481HDD#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 LT3481HDD#TRPBF?
For technical support, including LT3481HDD#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3481HDD#TRPBF requirements.
6.How does Aetrix verify that LT3481HDD#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3481HDD#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 LT3481HDD#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3481HDD#TRPBF?
All LT3481HDD#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3481HDD#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 LT3481HDD#TRPBF part is unused and in its original packaging.
Return procedure for LT3481HDD#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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