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Analog Devices Inc. LT3481EDD#TRPBF
- Part No.:
- LT3481EDD#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-WFDFN Exposed Pad
- Datasheet:
-
LT3481EDD#TRPBF.pdf
- Description:
- IC REG BUCK ADJ 2A 10DFN
- Quantity:
- Payment:
- Shipping:
Inventory:7,697
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Product details
Overview
LT3481EDD#TRPBF 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 output from 1.265V to 20V, and is used in automotive battery regulation and portable power supplies.
For engineers reviewing the LT3481EDD#TRPBF datasheet, LT3481EDD#TRPBF pinout, LT3481EDD#TRPBF application, or LT3481EDD#TRPBF equivalent, key selection criteria include input voltage range (3.6–34V), 2A output capability, thermal performance in the 3mm × 3mm DFN package, soft-start via RUN/SS, and Power Good flag functionality.
Technical Context
The LT3481EDD#TRPBF implements constant-frequency current-mode PWM control with an internal 0.18Ω NPN switch and integrated boost diode drive. Its oscillator supports programmable frequency from 300kHz to 2.8MHz via external RT resistor, and features frequency foldback during startup or overload to limit peak inductor current.
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 device includes active soft-start (via RC on RUN/SS), open-collector Power Good flag (90% VOUT threshold), and VC pin for loop compensation and current limit clamping.
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 pre-regulation. |
| Output Current | 2A continuous - sufficient for powering microcontrollers, FPGAs, and sensor subsystems from single-stage conversion. |
| Switching Frequency | 300kHz to 2.8MHz (RT-programmable) - enables compact magnetics: 1MHz allows ~4.7µH inductors and low-profile ceramic capacitors. |
| Quiescent Current | 50µA in Burst Mode at 12VIN→3.3VOUT - extends battery life in always-on portable and IoT edge devices. |
| Feedback Reference | 1.265V ±1.5% - sets output accuracy; allows precise 3.3V, 5V, or custom rails using standard 1% resistors. |
| Power Good Flag | Open-collector PG asserts high when VOUT ≥90% of target - provides reliable system reset and sequencing control without external comparators. |
| Shutdown Current | <1µA - ensures zero-load leakage in standby mode for energy-sensitive applications. |
| Package Thermal Resistance | θJA = 43°C/W (DFN) - requires minimal PCB copper area for thermal management at full 2A load. |
Pinout & Package
The LT3481EDD#TRPBF is housed in a 10-lead, 3mm × 3mm plastic DFN package with exposed pad (Pin 11), which must be soldered to GND for optimal thermal and electrical performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| BD (Pin 1) | Boost Diode Anode Connection | Connects external Schottky diode anode to enable BOOST capacitor charging; critical for NPN switch saturation. |
| BOOST (Pin 2) | Boost Drive Voltage Node | Provides >VIN voltage to internal NPN base; must exceed SW by ≥30V to ensure full switch conduction. |
| SW (Pin 3) | Switch Output Node | Drives inductor and catch diode; carries high di/dt pulsed current - requires short, low-inductance layout. |
| VIN (Pin 4) | Main Input Supply | Powers internal regulator and switch; requires local 4.7µF ceramic bypass close to pin. |
| RUN/SS (Pin 5) | Enable & Soft-Start Control | Logic-level shutdown input (≤0.2V = off); RC ramp here controls output voltage slew rate during startup. |
| PG (Pin 6) | Power Good Output | Open-collector flag pulled high externally; signals stable regulation after VOUT reaches 90% of setpoint. |
| BIAS (Pin 7) | Efficiency-Optimized Bias Source | Accepts VOUT (≥3V) to power internal circuitry - reduces VIN current and improves light-load efficiency. |
| FB (Pin 8) | Feedback Input | Regulated to 1.265V; connects to resistor divider - determines output voltage with ±1.5% reference tolerance. |
| VC (Pin 9) | Error Amplifier Output | Controls peak switch current; RC network to GND sets loop compensation and stability margins. |
| RT (Pin 10) | Frequency Programming Input | Resistor-to-GND sets switching frequency (300kHz–2.8MHz); enables EMI tuning and size optimization. |
Key Features
| Feature | Design Value |
|---|---|
| Low-Ripple Burst Mode | Maintains ≤15mV output ripple at light loads while drawing only 50µA from VIN - eliminates need for secondary LDO in battery-powered systems. |
| Integrated Boost Diode Drive | Eliminates external gate driver; BD/BOOST pins support standard Schottky diodes (e.g., Diodes Inc. PDS360) for full NPN switch saturation. |
| Saturating Switch Design | 0.18Ω on-resistance at 2A enables high efficiency (>85% at 12VIN→3.3VOUT/1A) without external MOSFETs or complex drive circuitry. |
| Thermally Enhanced DFN | 3mm × 3mm footprint with exposed GND pad achieves θJA = 43°C/W - supports 2A continuous output with minimal PCB area. |
| Programmable Soft-Start | RUN/SS pin accepts RC network to control output voltage ramp time - prevents inrush current and ensures clean power-up sequencing. |
| Power Good Flag with Hysteresis | PG asserts after VOUT reaches 90% of target and includes 5mV hysteresis - avoids chatter during marginal regulation or line transients. |
Applications
| Automotive Battery Regulation | Portable Product Power |
|---|---|
Use Scenario: Regulating 12V vehicle battery (9–16V nominal, up to 36V load dump) to 3.3V for infotainment MCU and CAN transceivers. IC Role / Device Role / Timing Role: Primary buck converter providing isolated, ripple-controlled 3.3V rail with Power Good signaling for safe boot sequence. Use Value: Withstands 36V transients, maintains 50µA quiescent current in sleep mode, and delivers 2A peak for burst processing - meets automotive ISO 7637-2 pulse requirements. | Use Scenario: Powering handheld medical sensors (e.g., pulse oximeter) from two AA batteries (1.8–3.2V) boosted to 5V, then stepped down to 3.3V for ADC and BLE radio. IC Role / Device Role / Timing Role: Secondary buck stage accepting regulated 5V input to generate ultra-low-noise 3.3V supply with soft-start for analog front-end stability. Use Value: Burst Mode extends battery life beyond 100 hours; BIAS pin connection to VOUT improves efficiency by 8–12% vs. VIN-biased operation. |
| Distributed Supply Regulation | Industrial Sensor Node Power |
Use Scenario: Local DC/DC conversion on a PLC I/O module board where 24V backplane is converted to 5V and 3.3V for digital logic and isolation interfaces. IC Role / Device Role / Timing Role: Point-of-load regulator delivering 2A at 5V with programmable 800kHz switching to minimize EMI near sensitive analog circuits. Use Value: RT pin allows EMI optimization; exposed DFN pad simplifies thermal design on dense industrial PCBs without heatsinks. | Use Scenario: Powering wireless vibration sensor nodes (MEMS accelerometer + LoRaWAN transceiver) deployed in factory machinery with 12–24V field wiring. IC Role / Device Role / Timing Role: Main power IC converting wide-input industrial supply to 3.3V for ultra-low-power microcontroller and RF subsystem. Use Value: 3.6–34V input range accommodates brownouts and surges; <1µA shutdown current enables multi-year battery operation in sleep state. |
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, 3mm × 4mm MSOP, no integrated boost diode drive - requires external bootstrap circuit. | Lacks BD/BOOST pins; needs external Schottky and capacitor - increases BOM count and layout complexity. | Choose when lower output current suffices and board space allows discrete bootstrap components. |
| MP2451DT-LF-Z | 36V input, 0.6A, 8-pin SOIC, no Power Good flag or BIAS pin - simpler feature set, lower cost. | No PG flag or BIAS efficiency enhancement; limited to sub-1A loads - unsuitable for 2A or sequencing-critical systems. | Choose for cost-sensitive, low-current applications where soft-start and power monitoring are not required. |
Compared with LTC3631EMSE#PBF and MP2451DT-LF-Z, the LT3481EDD#TRPBF uniquely combines 2A output, integrated boost drive, Power Good signaling, and BIAS-based efficiency optimization in a thermally efficient 3mm × 3mm DFN - making it optimal for space-constrained, high-reliability industrial and automotive point-of-load designs.
Availability
LT3481EDD#TRPBF 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 (–40°C to +85°C).
Supply support for LT3481EDD#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 legacy high-performance power management portfolio with rigorous qualification and long-term support.
The LT3481 belongs to Linear's monolithic current-mode buck regulator family, designed specifically for wide-input industrial and automotive applications demanding high efficiency at light loads, robust transient response, and integrated high-voltage switching capability.
FAQ
What is the maximum input voltage rating for LT3481EDD#TRPBF?
The LT3481EDD#TRPBF has an absolute maximum VIN rating of 36V. It operates continuously up to 34V; transient inputs up to 36V are acceptable only when the output is in regulation and no start-up or short-circuit events occur. Exceeding 34V during start-up or fault conditions may violate safe operating area limits. Always verify input transient profiles against the minimum switch on-time constraints per the datasheet's input voltage range equations.
Does LT3481EDD#TRPBF require an external Schottky diode?
Yes, the LT3481EDD#TRPBF requires an external Schottky diode connected between BD (Pin 1) and SW (Pin 3). The IC integrates the boost diode *drive* circuitry but not the diode itself. Diodes Inc. PDS360 or ON Semiconductor MBRM120E are validated choices. The diode must withstand peak reverse voltage equal to VIN and conduct average current determined by IOUT × (VIN – VOUT)/VIN.
How does the BIAS pin improve efficiency in LT3481EDD#TRPBF?
The BIAS pin on LT3481EDD#TRPBF allows the IC to draw bias current from VOUT (when ≥3V) instead of VIN, reducing total input current and improving light-load efficiency by 8–12%. This architecture is especially beneficial when VIN is significantly higher than VOUT (e.g., 24V→3.3V), as it avoids dissipating excess voltage across the internal regulator. Tie BIAS directly to the output capacitor for best results.
Can LT3481EDD#TRPBF synchronize to an external clock?
No, the LT3481EDD#TRPBF does not support external clock synchronization. Its oscillator is RT-resistor programmable from 300kHz to 2.8MHz but lacks a SYNC pin. However, it does offer frequency foldback during overload and soft-start via RUN/SS, enabling controlled startup and robust fault handling without external timing sources.
What is the thermal performance of LT3481EDD#TRPBF in its DFN package?
The LT3481EDD#TRPBF in the 3mm × 3mm DFN package has a junction-to-ambient thermal resistance (θJA) of 43°C/W when mounted on a standard 2-layer PCB with the exposed pad soldered to a 1-in² GND plane. At 2A output and 12VIN→3.3VOUT, typical power dissipation is ~0.6W, resulting in ~26°C junction-to-ambient rise - well within the –40°C to +85°C operating range. For higher ambient temperatures, increase copper area or add thermal vias under the exposed pad.
LT3481EDD#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 ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-DFN (3x3)
LT3481EDD#TRPBF FAQ
1.How can I place an order for LT3481EDD#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3481EDD#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 LT3481EDD#TRPBF reliable?
The price and inventory of LT3481EDD#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3481EDD#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3481EDD#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3481EDD#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3481EDD#TRPBF?
LT3481EDD#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3481EDD#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 LT3481EDD#TRPBF?
For technical support, including LT3481EDD#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3481EDD#TRPBF requirements.
6.How does Aetrix verify that LT3481EDD#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3481EDD#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 LT3481EDD#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3481EDD#TRPBF?
All LT3481EDD#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3481EDD#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 LT3481EDD#TRPBF part is unused and in its original packaging.
Return procedure for LT3481EDD#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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