Features and Benefits
- Wide Input Range: 3.6V to 34V Operating, 36V Maximum
- 2A Maximum Output Current
- Low Ripple Burst Mode® Operation
- 50µA IQ at 12VIN to 3.3VOUT
- Output Ripple < 15mV
- Adjustable Switching Frequency: 300kHz to 2.8MHz
- Low Shutdown Current: IQ < 1µA
- Integrated Boost Diode
- Power Good Flag
- Saturating Switch Design: 0.18Ω On-Resistance
- 1.265V Feedback Reference Voltage
- Output Voltage: 1.265V to 20V
- Soft-Start Capability
- Synchronizable Between 275kHz to 475kHz
- Small 10-Pin Thermally Enhanced MSOP and (3mm × 3mm) DFN Packages
The LT3481 is an adjustable frequency (300kHz to 2.8MHz) monolithic buck switching regulator that accepts input voltages up to 34V (36V maximum). A high efﬁciency 0.18Ω switch is included on the die along with a boost Schottky diode and the necessary oscillator, control, and logic circuitry. Current mode topology is used for fast transient response and good loop stability. Low ripple Burst Mode operation maintains high efﬁciency at low output currents while keeping output ripple below 15mV in a typical application. In addition, the LT3481 can further enhance low output current efﬁciency by drawing bias current from the output when VOUT is above 3V. Shutdown reduces input supply current to less than 1µA while a resistor and capacitor on the RUN/SS pin provide a controlled output voltage ramp (soft-start). A power good ﬂag signals when VOUT reaches 90% of the programmed output voltage. The LT3481 is available in 10-Pin MSOP and 3mm × 3mm DFN packages with exposed pads for low thermal resistance.
- Automotive Battery Regulation
- Power for Portable Products
- Distributed Supply Regulation
- Industrial Supplies
- Wall Transformer Regulation
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (1)
Demonstration circuit 857 features the LT3481EMSE and LT3481EDD in two step-down converter circuits, one configured for high efficiency and the other for small size. The high efficiency circuit switching at 800kHz is designed for 3.3V/2A output from a 4.5V to 34V input. The small size circuit switching at 2MHz demonstrates the LT3481’s ability to operate with a small inductor and output capacitor. It is designed for 5V output from an 8.5V to 22V input. The wide input range of the LT3481 allows a variety of input sources. The typical sources are automotive batteries, wall adaptors and industrial supplies. The current mode control scheme creates fast transient response and good loop stability. In addition, the LT3481’s integrated boost diode reduces the parts count. The low ripple Burst Mode® Operation of LT3481 not only allows the circuit to have high efficiency over a broad current range but also provides the low output ripple at light load conditions.
Tools & Simulations
LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.
To launch ready-to-run LTspice demonstration circuits for this part:
Step 1: Download and install LTspice on your computer.
Step 2: Click on the link in the section below to download a demonstration circuit.
Step 3: If LTspice does not automatically open after clicking the link below, you can instead run the simulation by right clicking on the link and selecting “Save Target As.” After saving the file to your computer, start LTspice and open the demonstration circuit by selecting ‘Open’ from the ‘File’ menu.
Models for the following parts are available in LTspice:
LTpowerCAD® is a power supply design program which selects power stage components, provides detailed power efficiency, shows quick loop Bode plot stability and load transient analysis, and can export to LTspice for simulation.
Design tools for the following parts are available in LTpowerCAD:
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.
Sample & Buy
The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.