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Analog Devices Inc. LT3481EMSE#PBF
- Part No.:
- LT3481EMSE#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT3481EMSE#PBF.pdf
- Description:
- IC REG BUCK ADJ 2A 10MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,102
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Product details
Overview
LT3481EMSE#PBF from Analog Devices (formerly Linear Technology) is a monolithic 300kHz–2.8MHz current-mode step-down switching regulator with integrated 0.18Ω NPN switch and boost Schottky diode, supporting 3.6V–34V input and delivering up to 2A output current at adjustable 1.265V–20V. It features 50μA quiescent current in Burst Mode, power good flag, soft-start via RUN/SS pin, and operates in thermally enhanced 10-lead MSOP package rated for –40°C to +85°C.
For engineers reviewing the LT3481EMSE#PBF datasheet, LT3481EMSE#PBF pinout, LT3481EMSE#PBF application, or LT3481EMSE#PBF equivalent, key selection considerations include its wide-input automotive-grade buck capability, low-IQ light-load efficiency, integrated bias-sourcing architecture, and thermal performance in the exposed-pad MSOP package.
Technical Context
The LT3481EMSE#PBF implements constant-frequency current-mode control with internal error amplifier, slope compensation, and active VC-pin current limiting. Its oscillator frequency is resistor-programmable (RT pin) from 300kHz to 2.8MHz, enabling optimization of inductor size versus efficiency and dropout voltage.
It uses bipolar NPN switch topology driven by BOOST pin voltage (up to 56V), with integrated Schottky bootstrap diode (BD pin). Bias current can be drawn from VOUT (≥3V) via BIAS pin to improve efficiency at high VIN/VOUT ratios, and shutdown draws <1μA from VIN.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.6V to 34V operating; 36V absolute max - supports automotive battery transients and industrial wide-input rails. |
| Output Current | Up to 2A continuous - sufficient for FPGA core supplies, DSPs, and point-of-load regulation in portable systems. |
| Quiescent Current | 50μA at 12VIN/3.3VOUT in Burst Mode - enables >10-year battery life in always-on sensor nodes. |
| Switching Frequency | 300kHz to 2.8MHz (RT-programmable) - allows compact 1–4.7μH inductors and reduces EMI filtering burden. |
| Feedback Reference | 1.265V ±15mV - enables precise output regulation from 1.265V to 20V using standard resistor dividers. |
| Power Good Flag | Open-collector PG asserts when VFB reaches 90% of target - provides reliable system power sequencing without external monitoring. |
| Thermal Package | 10-lead MSOP with exposed pad (θJA = 40°C/W) - delivers 2A output with minimal heatsinking in space-constrained layouts. |
Pinout & Package
LT3481EMSE#PBF is housed in a 10-lead plastic MSOP package with exposed thermal pad (Pin 11) that must be soldered to PCB ground for optimal thermal performance (θJA = 40°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BD (Pin 1) | Boost diode anode connection | Connects external Schottky diode anode to form bootstrap charge path for BOOST pin. |
| BOOST (Pin 2) | Switch driver supply | Provides >VIN voltage to fully saturate internal NPN switch; max 56V rating. |
| SW (Pin 3) | Switch node | Drives inductor and catch diode; carries full switching current and high dv/dt. |
| VIN (Pin 4) | Main power input | Supplies internal regulator and switch; requires local 4.7μF ceramic bypass. |
| RUN/SS (Pin 5) | Enable & soft-start control | Logic-level enable (≥2.5V); RC ramp on this pin controls output voltage slew rate. |
| PG (Pin 6) | Power good indicator | Open-collector output active-low until VOUT reaches 90% of regulation target. |
| BIAS (Pin 7) | Bias supply input | Accepts ≥3V external source (e.g., VOUT) to reduce VIN current and improve efficiency. |
| FB (Pin 8) | Feedback input | Regulated to 1.265V; connects to resistor divider for output voltage programming. |
| VC (Pin 9) | Error amplifier output | Controls peak switch current; RC compensation network sets loop stability. |
| RT (Pin 10) | Frequency set resistor | Grounded resistor programs switching frequency from 300kHz to 2.8MHz. |
Key Features
| Feature | Design Value |
|---|---|
| Low-Ripple Burst Mode | Maintains <15mV output ripple at light loads while holding IQ to 50μA - eliminates audible noise and extends battery runtime. |
| Integrated Boost Diode | On-chip Schottky diode eliminates external BD component - reduces BOM count and layout area in compact designs. |
| Bias-Sourcing Architecture | Draws regulator bias current from VOUT (when ≥3V) instead of VIN - improves full-load efficiency by up to 3% at high input voltages. |
| Saturating Switch Design | 0.18Ω on-resistance NPN switch - minimizes conduction loss and thermal rise at 2A load in MSOP package. |
| Programmable Frequency Foldback | Reduces switching frequency during startup or overload - limits peak inductor current and prevents saturation under fault conditions. |
Applications
| Automotive Battery Regulation | Portable Product Power |
|---|---|
|
Use Scenario: Regulating 12V/24V vehicle battery to 3.3V/5V for infotainment microcontrollers and CAN transceivers. IC Role / Device Role / Timing Role: Primary buck converter providing stable, transient-robust DC supply with cold-crank support down to 3.6V. Use Value: Withstands 36V load-dump transients and maintains regulation during engine cranking (4.5V–34V range), reducing need for upstream TVS clamping. |
Use Scenario: Powering ARM Cortex-M4-based handheld medical devices with Li-ion battery input (3.0V–4.2V) and dual-rail outputs. IC Role / Device Role / Timing Role: Main system regulator delivering 1.8V and 3.3V from single-cell battery via adjustable feedback and BIAS pin optimization. Use Value: 50μA Burst Mode IQ extends battery life beyond 30 days in sleep mode; soft-start prevents inrush into capacitive loads. |
| Distributed Supply Regulation | Industrial Sensor Node Power |
|
Use Scenario: Generating local 5V/12V rails from 24V factory bus for PLC I/O modules and fieldbus interfaces. IC Role / Device Role / Timing Role: Point-of-load regulator with programmable frequency (800kHz) to avoid EMI-sensitive bands and simplify filter design. Use Value: RT-programmable switching frequency allows EMI compliance tuning without changing magnetics; exposed-pad MSOP aids thermal management in sealed enclosures. |
Use Scenario: Powering ultra-low-power wireless sensor nodes (LoRaWAN, NB-IoT) with intermittent 2A burst loads and years-long battery requirements. IC Role / Device Role / Timing Role: High-efficiency buck converter with BIAS pin connected to regulated 3.3V rail to minimize total system IQ. Use Value: Draws bias current from VOUT, reducing VIN supply current by ~30μA vs. conventional buck - critical for sub-100μA average system current targets. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT8610EMSE#PBF | 42V input, 3.5A, 2MHz sync rectification, 2.5μA IQ; requires external MOSFET drivers and compensation. | Higher current, lower IQ, but larger solution size and higher cost; no integrated boost diode. | Select for new designs requiring <3μA shutdown current and 3.5A output; not drop-in due to different pinout and control architecture. |
| TPS54202DRCT | 28V input, 2A, 500kHz–2.2MHz, 18μA IQ; integrated FETs, no BOOST/Bias architecture. | Lacks bias-sourcing capability and BOOST pin - less efficient at high VIN/VOUT ratios; smaller DFN package. | Prefer for cost-sensitive consumer applications where 3.6V–28V input suffices and 50μA IQ is acceptable; no pin compatibility. |
Compared with LT3481EMSE#PBF, LT8610EMSE#PBF offers superior light-load efficiency and higher current but requires redesign for layout and compensation; TPS54202DRCT simplifies BOM with integrated FETs but sacrifices bias-sourcing efficiency and automotive transient robustness.
Availability
LT3481EMSE#PBF is available at Aetrix Electronics and suitable for automotive battery regulation, portable product power, and distributed supply regulation requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LT3481EMSE#PBF 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-reliability analog and power management portfolio with rigorous qualification and long-term product support.
The LT3481EMSE#PBF belongs to Linear's monolithic buck regulator family designed for wide-input industrial and automotive applications where integration, thermal performance, and light-load efficiency are critical.
FAQ
What is the maximum input voltage rating for LT3481EMSE#PBF?
The LT3481EMSE#PBF has an absolute maximum VIN rating of 36V. It operates continuously from 3.6V to 34V, and can withstand 36V transients when in regulation - making it suitable for 24V automotive systems with load-dump protection requirements. The BOOST pin supports up to 56V, enabling robust bootstrap operation even under high-VIN conditions.
How does the BIAS pin improve efficiency in LT3481EMSE#PBF?
The BIAS pin on LT3481EMSE#PBF allows the IC to draw bias current from the regulated output (if ≥3V) instead of VIN. This reduces total input current - especially beneficial at high VIN/VOUT ratios - improving full-load efficiency by up to 3%. In a 24V-to-3.3V design, this architecture lowers power dissipation and thermal stress compared to conventional buck regulators.
Does LT3481EMSE#PBF support synchronization to an external clock?
No, LT3481EMSE#PBF does not support external clock synchronization. Its oscillator is resistor-programmable (via RT pin) from 300kHz to 2.8MHz but lacks a SYNC pin. However, it does feature frequency foldback during startup and overload to limit inductor current - a distinct protection mechanism separate from synchronization.
What is the purpose of the exposed pad on the LT3481EMSE#PBF MSOP package?
The exposed pad (Pin 11) on LT3481EMSE#PBF is electrically and thermally connected to GND. It must be soldered to a PCB copper pour to achieve the specified θJA of 40°C/W. This thermal path is essential for sustaining 2A output current without exceeding the 125°C maximum junction temperature - particularly in enclosed or high-ambient environments.
Can LT3481EMSE#PBF operate in discontinuous conduction mode (DCM)?
Yes, LT3481EMSE#PBF can operate in DCM at light loads or with small inductors. Its current-mode architecture remains stable in DCM, and Burst Mode operation inherently transitions into pulse-skipping behavior below ~10mA load. DCM reduces switching losses but lowers maximum achievable output current - design guidance in the datasheet recommends ΔIL ≈ 0.4×IOUT(MAX) for optimal CCM operation.
LT3481EMSE#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width) Exposed Pad
- Packaging:
- Tube
- 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 ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-MSOP-EP
LT3481EMSE#PBF FAQ
1.How can I place an order for LT3481EMSE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3481EMSE#PBF 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 LT3481EMSE#PBF reliable?
The price and inventory of LT3481EMSE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3481EMSE#PBF is usually 5 days.
3.What payment methods are accepted for LT3481EMSE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3481EMSE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3481EMSE#PBF?
LT3481EMSE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3481EMSE#PBF 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 LT3481EMSE#PBF?
For technical support, including LT3481EMSE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3481EMSE#PBF requirements.
6.How does Aetrix verify that LT3481EMSE#PBF is sourced from the original manufacturer or authorized distributors?
All LT3481EMSE#PBF 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 LT3481EMSE#PBF meets industry standards.
7.What is the process for return or replacement of LT3481EMSE#PBF?
All LT3481EMSE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3481EMSE#PBF, 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 LT3481EMSE#PBF part is unused and in its original packaging.
Return procedure for LT3481EMSE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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