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Analog Devices Inc. LT3481HMSE#TRPBF
- Part No.:
- LT3481HMSE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT3481HMSE#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 2A 10MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,268
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Product details
Overview
LT3481HMSE#TRPBF from Analog Devices (formerly Linear Technology) is a 36V, 2A, 2.8MHz monolithic step-down switching regulator with current-mode control, integrated 0.18Ω bipolar NPN switch and boost Schottky diode, designed for automotive battery regulation and industrial supplies requiring wide input range (3.6V–34V) and low quiescent current (50µA in Burst Mode).
For engineers reviewing the LT3481HMSE#TRPBF datasheet, LT3481HMSE#TRPBF pinout, LT3481HMSE#TRPBF application, or LT3481HMSE#TRPBF equivalent, key selection criteria include guaranteed operation up to 150°C junction temperature, adjustable frequency (300kHz–2.8MHz) via RT resistor, power good flag, soft-start capability, and thermally enhanced 10-lead MSOP package with exposed pad.
Technical Context
The LT3481HMSE#TRPBF implements constant-frequency current-mode PWM control using an internal error amplifier that regulates FB to 1.265V and drives VC to modulate peak switch current. Its oscillator supports external frequency programming (RT pin) and foldback during startup/overload.
It integrates a boost capacitor drive circuit (BOOST/SW/BD pins) enabling full saturation of the internal bipolar switch, and features low-ripple Burst Mode operation that maintains output ripple <15mV while drawing only 50µA from VIN at light load (12VIN→3.3VOUT), with bias current drawn from VOUT when >3V to improve efficiency.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.6V to 34V operating; 36V absolute max - supports automotive cold-crank and industrial unregulated rails. |
| Max Output Current | 2A continuous - sufficient for powering microcontrollers, sensors, and interface ICs in embedded systems. |
| Switching Frequency | Adjustable 300kHz to 2.8MHz via RT resistor - enables optimization of inductor size vs. efficiency and EMI profile. |
| Quiescent Current | 50µA in Burst Mode (12VIN→3.3VOUT) - extends battery life in portable and always-on applications. |
| Feedback Reference | 1.265V ±15mV over –40°C to 150°C - enables precise output voltage setting from 1.265V to 20V using external resistors. |
| Power Good Flag | Open-collector PG asserts high when VOUT reaches 90% of programmed value - provides reliable system power sequencing signal. |
| Thermal Rating | –40°C to 150°C junction temperature (H-grade) - qualified for under-hood automotive and high-temp industrial environments. |
Pinout & Package
LT3481HMSE#TRPBF is housed in a thermally enhanced 10-lead MSOP package (MSE) with exposed pad (Pin 11) soldered to PCB ground for low θJA = 40°C/W. Pin numbering follows standard top-view MSOP layout.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BD (1) | Boost Diode Anode Connection | Connects external Schottky diode anode to generate boosted gate drive voltage for internal switch saturation. |
| BOOST (2) | Boost Capacitor Drive Node | Provides >VIN voltage to internal switch base; must be ≥30V above SW pin and ≤56V absolute. |
| SW (3) | Internal Switch Collector Output | Drives external inductor and catch diode; carries full switched current and requires low-inductance layout. |
| VIN (4) | Main Input Supply | Supplies internal regulator and switch; bypass with ≥4.7µF ceramic capacitor close to pin. |
| RUN/SS (5) | Enable & Soft-Start Control | Logic-level enable (≥2.5V = on); RC network here sets controlled output voltage ramp time. |
| PG (6) | Power Good Open-Collector Output | Sinks current when VOUT < 90% of target; requires external pull-up for system monitoring. |
| BIAS (7) | Efficiency-Optimized Bias Input | Draws internal regulator current from VOUT (if >3V), reducing VIN current and improving light-load efficiency. |
| FB (8) | Feedback Voltage Sense | Regulated to 1.265V; connects to resistor divider tap for output voltage programming. |
| VC (9) | Error Amplifier Output | Controls peak switch current; RC compensation network here stabilizes loop dynamics. |
| RT (10) | Oscillator Frequency Set | Resistor to ground programs switching frequency from 300kHz to 2.8MHz per datasheet table. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Boost Schottky Diode | Eliminates external boost diode, reducing BOM count and PCB area while ensuring reliable switch saturation. |
| Low-Ripple Burst Mode Operation | Maintains output ripple <15mV at light loads without sacrificing 50µA quiescent current performance. |
| Saturating Bipolar NPN Switch | 0.18Ω on-resistance enables high efficiency at 2A load without requiring external MOSFET drivers. |
| Thermally Enhanced MSOP Package | Exposed pad and θJA = 40°C/W allow full 2A operation at 150°C junction temperature in compact footprint. |
| Programmable Soft-Start | Controlled output voltage ramp via RUN/SS RC network prevents inrush current and ensures clean power-up sequencing. |
Applications
| Automotive Battery Regulation | Industrial Power Supplies |
|---|---|
Use Scenario: Regulating 12V/24V automotive battery rail (including cold-crank down to 3.6V) to 3.3V or 5V for infotainment ECUs and ADAS sensors. IC Role / Device Role / Timing Role: Primary buck converter providing stable, sequenced, and monitored DC power under wide temperature and transient conditions. Use Value: H-grade 150°C rating and 36V transient tolerance ensure reliability in under-hood environments; PG flag enables safe MCU boot sequencing. | Use Scenario: Converting unregulated 24V factory floor supply to 5V for PLC I/O modules and industrial Ethernet PHYs. IC Role / Device Role / Timing Role: High-efficiency, wide-input DC-DC stage delivering regulated power with minimal heatsinking in space-constrained enclosures. Use Value: 2A output and 50µA Burst Mode current support both active and standby states; adjustable frequency avoids sensitive EMI bands. |
| Portable Product Power | Distributed Supply Regulation |
Use Scenario: Powering handheld test equipment with Li-ion battery input (3.6V–4.2V) and 3.3V logic rail requirement. IC Role / Device Role / Timing Role: Efficient step-down regulator minimizing battery drain during long-duration measurements and sleep modes. Use Value: 50µA quiescent current extends battery runtime; BIAS pin operation improves efficiency when VOUT > 3V. | Use Scenario: Local point-of-load conversion in telecom line cards where 48V backplane is stepped to 12V/5V for FPGA and SerDes supplies. IC Role / Device Role / Timing Role: Compact, high-frequency buck regulator enabling small inductors and fast transient response to digital load steps. Use Value: 2.8MHz max switching frequency allows use of sub-5mm inductors; current-mode control ensures stability across varying line/load conditions. |
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 input, 1.5A, 3MHz, 25µA IQ, no integrated boost diode; requires external bootstrap cap/diode. | Better light-load efficiency but lower current rating and no internal boost diode - increases BOM and layout complexity. | Select when ultra-low IQ (<30µA) and higher frequency (>2.8MHz) are critical, and board space allows external components. |
| TPS54202DRCT | 28V input, 2A, 500kHz–2.5MHz, 2µA shutdown, FET-based, no BIAS pin or PG flag. | Lower max input voltage and no power good output; lacks thermal grade beyond 125°C - unsuitable for automotive under-hood. | Select for cost-sensitive industrial applications within 28V input range and where PG signaling is not required. |
Compared with LTC3631EMSE#PBF and TPS54202DRCT, LT3481HMSE#TRPBF uniquely combines 36V input, 2A output, integrated boost diode, power good flag, BIAS pin efficiency enhancement, and 150°C operation - making it optimal for ruggedized, self-contained buck designs where reliability and integration outweigh marginal IQ savings.
Availability
LT3481HMSE#TRPBF is available at Aetrix Electronics and suitable for automotive battery regulation, industrial power supplies, and portable product power requiring stable component supply with extended temperature qualification and long-term lifecycle support.
Supply support for LT3481HMSE#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 with rigorous automotive and industrial qualification standards.
The LT3481 product line delivers monolithic, high-voltage buck regulators optimized for harsh-environment applications including automotive, industrial, and avionics systems requiring wide input range, high temperature operation, and integrated functionality.
FAQ
What is the maximum junction temperature rating for LT3481HMSE#TRPBF?
The LT3481HMSE#TRPBF is rated for operation up to 150°C junction temperature (H-grade), with guaranteed specifications over –40°C to 150°C ambient. This makes LT3481HMSE#TRPBF suitable for under-hood automotive and high-temperature industrial environments where standard commercial or industrial grade parts would fail.
Does LT3481HMSE#TRPBF require an external boost diode?
No, LT3481HMSE#TRPBF integrates the boost Schottky diode internally. The BD pin connects directly to the anode of this internal diode, eliminating the need for an external component and simplifying layout. External components required are only the boost capacitor (between BOOST and SW) and the main inductor/catch diode.
How does the BIAS pin improve efficiency in LT3481HMSE#TRPBF?
The BIAS pin on LT3481HMSE#TRPBF allows the internal regulator to draw bias current from VOUT (when >3V) instead of VIN, reducing input supply current and improving light-load efficiency. In a 12V→3.3V application, this architecture lowers quiescent current significantly compared to VIN-only biasing.
What is the function of the RT pin on LT3481HMSE#TRPBF?
The RT pin on LT3481HMSE#TRPBF sets the switching frequency by connecting an external resistor to ground. Values from 8.66kΩ (2.8MHz) to 187kΩ (300kHz) program the oscillator, enabling design trade-offs between inductor size, efficiency, EMI, and dropout voltage - all while maintaining current-mode stability.
Can LT3481HMSE#TRPBF operate with input transients up to 36V?
Yes, LT3481HMSE#TRPBF supports 36V absolute maximum input voltage during normal regulation. However, during startup or short-circuit conditions, the safe maximum is 34V unless the switching frequency is reduced to accommodate minimum on-time constraints - as detailed in the Absolute Maximum Ratings and Applications Information sections of the datasheet.
LT3481HMSE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width) 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-MSOP-EP
LT3481HMSE#TRPBF FAQ
1.How can I place an order for LT3481HMSE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3481HMSE#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 LT3481HMSE#TRPBF reliable?
The price and inventory of LT3481HMSE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3481HMSE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3481HMSE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3481HMSE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3481HMSE#TRPBF?
LT3481HMSE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3481HMSE#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 LT3481HMSE#TRPBF?
For technical support, including LT3481HMSE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3481HMSE#TRPBF requirements.
6.How does Aetrix verify that LT3481HMSE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3481HMSE#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 LT3481HMSE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3481HMSE#TRPBF?
All LT3481HMSE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3481HMSE#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 LT3481HMSE#TRPBF part is unused and in its original packaging.
Return procedure for LT3481HMSE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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