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Analog Devices Inc. LT3481EDD#PBF
- Part No.:
- LT3481EDD#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-WFDFN Exposed Pad
- Datasheet:
-
LT3481EDD#PBF.pdf
- Description:
- IC REG BUCK ADJ 2A 10DFN
- Quantity:
- Payment:
- Shipping:
Inventory:542
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Product details
Overview
LT3481EDD#PBF from Analog Devices (formerly Linear Technology) is a monolithic 36V, 2A step-down switching regulator with current-mode control, 2.8MHz max switching frequency, 50µA quiescent current in Burst Mode, and integrated boost Schottky diode. It operates from 3.6V to 34V input, delivers adjustable 1.265V–20V output, and targets automotive battery regulation and portable power supplies.
For engineers reviewing the LT3481EDD#PBF datasheet, LT3481EDD#PBF pinout, LT3481EDD#PBF application, or LT3481EDD#PBF equivalent, key selection criteria include its 0.18Ω internal switch RDS(on), 1.265V feedback reference, soft-start via RUN/SS pin, power-good flag, and thermal performance in the 3mm × 3mm DFN package with exposed pad.
Technical Context
The LT3481EDD#PBF uses constant-frequency current-mode PWM control with oscillator frequency set by an external RT resistor (300kHz–2.8MHz). Its bipolar NPN power switch is driven via an integrated boost circuit requiring external BOOST capacitor and Schottky diode.
Burst Mode operation reduces quiescent current to 50µA at light loads while maintaining output ripple below 15mV; bias current can be drawn from VOUT when >3V to improve efficiency. The VC pin provides error amplifier output for loop compensation, and PG signals when VOUT reaches 90% of regulation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.6V to 34V operating; 36V absolute maximum - supports wide-range industrial and automotive inputs. |
| Max Output Current | 2A continuous - sufficient for powering microcontrollers, FPGAs, and sensor subsystems. |
| Switching Frequency | Adjustable 300kHz to 2.8MHz via RT pin - enables optimization of inductor size vs. efficiency. |
| Quiescent Current | 50µA in Burst Mode at 12VIN/3.3VOUT - extends battery life in always-on portable systems. |
| Feedback Reference | 1.265V ±15mV - sets precise output voltage with standard resistor divider networks. |
| Power Good Flag | Open-collector PG asserts high when VOUT ≥ 90% of programmed value - enables system sequencing and fault monitoring. |
| Internal Switch RON | 0.18Ω typical - minimizes conduction loss at full load, supporting high-efficiency 2A operation. |
| Package Thermal Resistance | θJA = 43°C/W (DFN) - requires exposed pad soldered to PCB ground plane for reliable 2A operation. |
Pinout & Package
LT3481EDD#PBF is housed in a 10-lead, 3mm × 3mm plastic DFN package with exposed thermal pad (Pin 11), which must be connected to GND for thermal and electrical integrity. Package outline and pin numbering follow JEDEC MO-229WAY.
| 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. |
| BOOST (2) | Boost capacitor node | Provides >VIN voltage to fully saturate internal bipolar NPN switch; rated to 56V max. |
| SW (3) | Switch node | Drives external inductor and catch diode; carries full switching current and voltage stress. |
| VIN (4) | Main power input | Supplies internal regulator and switch; bypass locally with ≥4.7µF ceramic capacitor. |
| RUN/SS (5) | Enable & soft-start control | Logic-level shutdown (<0.2V) and controlled VOUT ramp via external R-C network. |
| PG (6) | Power-good open-collector output | Sinks current when VOUT < 90% of target; requires external pull-up for system monitoring. |
| BIAS (7) | Bias supply input | Accepts VOUT ≥3V to reduce VIN current draw and improve light-load efficiency. |
| FB (8) | Feedback input | Regulated to 1.265V; connects to resistor divider tap for output voltage programming. |
| VC (9) | Error amplifier output | Controls peak switch current; used with RC network to stabilize control loop. |
| RT (10) | Oscillator frequency set | Resistor-to-ground sets switching frequency from 300kHz to 2.8MHz. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Boost Schottky Diode | Eliminates external boost diode, reducing BOM count and layout area in compact DFN footprint. |
| Low-Ripple Burst Mode Operation | Maintains <15mV output ripple at light loads while achieving 50µA IQ, critical for battery-powered standby modes. |
| Adjustable Switching Frequency | 300kHz–2.8MHz range allows trade-off between inductor size (smaller at high fSW) and efficiency (higher at low fSW). |
| Thermally Enhanced DFN Package | 3mm × 3mm body with exposed GND pad achieves θJA = 43°C/W - enables 2A operation without heatsink in space-constrained designs. |
| Power-Good Flag with Hysteresis | PG output includes 5mV hysteresis and valid indication only when VIN > 3.5V and RUN/SS enabled - prevents false sequencing signals. |
| Soft-Start via RUN/SS Pin | External R-C network on RUN/SS controls output voltage ramp rate, limiting inrush current into output capacitors. |
Applications
| Automotive Battery Regulation | Portable Product Power |
|---|---|
Use Scenario: Regulating 12V or 24V vehicle battery to 3.3V/5V for infotainment MCU and CAN transceivers under cold-crank (5.5V) and load-dump (36V) conditions. IC Role / Device Role / Timing Role: Primary buck converter providing stable, low-noise DC power with robust input transient handling and thermal resilience. Use Value: 36V absolute max rating and –40°C to 85°C operating range ensure reliability across automotive temperature extremes and voltage surges. | Use Scenario: Powering handheld medical devices or IoT sensors from single-cell Li-ion (4.2V) or dual-cell packs (8.4V), requiring long runtime and low standby drain. IC Role / Device Role / Timing Role: High-efficiency step-down regulator delivering regulated output while minimizing quiescent consumption during sleep states. Use Value: 50µA Burst Mode IQ and BIAS pin operation from VOUT extend battery life significantly versus conventional buck controllers. |
| Distributed Supply Regulation | Industrial Power Supplies |
Use Scenario: Local point-of-load conversion in PLC backplanes or motor drives where 24V bus powers multiple 5V/3.3V subsystems with varying load profiles. IC Role / Device Role / Timing Role: Compact, thermally efficient buck regulator enabling board-level power distribution without centralized DC/DC modules. Use Value: 2A capability, adjustable frequency, and DFN package allow dense placement near noise-sensitive analog or digital loads. | Use Scenario: Replacing linear regulators in factory automation equipment requiring 5V/12V rails from unregulated 24V or 48V industrial supplies with high ambient temperatures. IC Role / Device Role / Timing Role: Efficient switching regulator replacing inefficient LDOs to reduce heat generation and improve system thermal margin. Use Value: 0.18Ω switch RON, 125°C junction rating, and exposed-pad DFN support continuous 2A operation at elevated ambient temperatures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3630EMSE#PBF | Higher 36V input, 1.5A output; integrated MOSFETs; no boost diode required; 3mm × 4mm MSOP. | Lower output current; lacks BIAS pin for efficiency optimization; different pinout and compensation scheme. | Select when lower IQ (15µA) and integrated MOSFETs outweigh need for 2A output and BIAS-driven efficiency. |
| MP2451DT-LF-Z | 36V input, 0.6A output; 2MHz fixed frequency; smaller 8-pin SOIC; no PG or BIAS pins. | Not suitable for 2A loads; lacks power-good signaling and bias-input efficiency enhancement. | Select only for cost-sensitive, low-current applications where PG, BIAS, and 2A capability are unnecessary. |
Compared with LTC3630EMSE#PBF and MP2451DT-LF-Z, LT3481EDD#PBF uniquely combines 2A output, 50µA Burst Mode IQ, BIAS pin efficiency boost, and PG flag in a thermally optimized 3mm × 3mm DFN - making it optimal for space-constrained, high-reliability 2A buck applications demanding full feature integration.
Availability
LT3481EDD#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 LT3481EDD#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-performance power management portfolio with rigorous qualification and long-term support.
The LT3481EDD#PBF belongs to Linear's monolithic buck regulator family designed for wide-input, high-efficiency DC/DC conversion in automotive, industrial, and portable systems where thermal density and light-load efficiency are critical.
FAQ
What is the maximum input voltage rating for LT3481EDD#PBF?
The LT3481EDD#PBF has an absolute maximum input voltage of 36V. It operates continuously up to 34V; transient 36V inputs are acceptable only when the output is in regulation and no startup or short-circuit events occur. Exceeding 36V risks permanent damage per Absolute Maximum Ratings.
Does LT3481EDD#PBF require an external boost diode?
Yes, the LT3481EDD#PBF requires an external Schottky diode connected between BD (Pin 1) and BOOST (Pin 2). Although the datasheet states "integrated boost Schottky diode", this refers to on-die integration of the diode's cathode and driver circuitry - the anode (BD pin) must connect to an external discrete Schottky diode to generate the boosted gate drive voltage.
How is soft-start implemented on LT3481EDD#PBF?
Soft-start on LT3481EDD#PBF is implemented using an external resistor and capacitor connected to the RUN/SS pin (Pin 5). When enabled, the internal circuit ramps the RUN/SS voltage, which clamps the VC pin voltage and limits peak switch current during startup - controlling the output voltage slew rate and minimizing inrush current into output capacitors.
What is the function of the BIAS pin on LT3481EDD#PBF?
The BIAS pin (Pin 7) on LT3481EDD#PBF accepts an external voltage ≥3V - typically the regulated output - to power the internal bias regulator. This reduces current drawn from VIN, improving light-load efficiency. When VBIAS < 3V or unconnected, the device draws bias current from VIN instead.
Can LT3481EDD#PBF synchronize to an external clock?
No, LT3481EDD#PBF does not support external clock synchronization. Its oscillator is resistor-programmed (via RT pin) and operates from 300kHz to 2.8MHz, but lacks a SYNC pin or digital interface for external clock injection. Synchronization capability is absent in all LT3481 variants per the datasheet Electrical Characteristics and Pin Functions sections.
LT3481EDD#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 10-WFDFN 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-DFN (3x3)
LT3481EDD#PBF FAQ
1.How can I place an order for LT3481EDD#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3481EDD#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 LT3481EDD#PBF reliable?
The price and inventory of LT3481EDD#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3481EDD#PBF is usually 5 days.
3.What payment methods are accepted for LT3481EDD#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3481EDD#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3481EDD#PBF?
LT3481EDD#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3481EDD#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 LT3481EDD#PBF?
For technical support, including LT3481EDD#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3481EDD#PBF requirements.
6.How does Aetrix verify that LT3481EDD#PBF is sourced from the original manufacturer or authorized distributors?
All LT3481EDD#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 LT3481EDD#PBF meets industry standards.
7.What is the process for return or replacement of LT3481EDD#PBF?
All LT3481EDD#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3481EDD#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 LT3481EDD#PBF part is unused and in its original packaging.
Return procedure for LT3481EDD#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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