Features and Benefits
- Wide Input Range:
- Operation from 3.6V to 36V
- Over-Voltage Lockout Protects Circuits through 60V Transient
- 2A Maximum Output Current
- Low Ripple Burst Mode® Operation
- 70µA IQ at 12VIN to 3.3VOUT
- Output Ripple < 15mV
- Adjustable Switching Frequency: 200kHz to 2.4MHz
- Low Shutdown Current: IQ < 1µA
- Integrated Boost Diode
- Synchronizable Between 250kHz to 2MHz
- Power Good Flag
- Saturating Switch Design: 0.25Ω On-Resistance
- 0.790V Feedback Reference Voltage
- Output Voltage: 0.79V to 20V
- Soft-Start Capability
- Small 10-Pin Thermally Enhanced MSOP and (3mm × 3mm) DFN Packages
The LT3480 is an adjustable frequency (200kHz to 2.4MHz) monolithic buck switching regulator that accepts input voltages up to 36V (60V maximum). A high efficiency 0.25Ω 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 LT3480 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 86% of the programmed output voltage. The LT3480 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
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 (3)
Demonstration Circuit 1394A shows how the LT3480 high voltage step-down regulator can be used with the LTC4098 USB-compatible Li-Ion battery charger to design a 2 input source battery charger circuit that also provides power to the load from the LT3480, a 5V wall adapter or the batteries based on available power. The LTC4098 interfaces with a number of ADI switching regulators to provide a high efficiency, high voltage power path. The LT3480 operates from 8V to 38V (60V transients) and provides 2A with a voltage range that is mode and load dependent.
Demonstration circuit 1212A-A is a monolithic step-down DC/DC switching regulatro featuring the LT3480 in the 3 × 3 DFN-10 package. The demo board provides 5V at 2A from a 6.3V to 38V input and has transient protection up to 60V. The demo boards default switching frequency is 800kHz, but the LT3480 has a SYNC pin which allows frequency synchronization to an external clock over a 250kHz to 2MHz range. The LT3480's quiescent current is 70uA, while the LT3685 has a 0.9mA quiescent current.
An EMC filter at the input makes the circuit compatible with EMC standard EN55022 Class B.
Demonstration circuit 1091 is a monolithic step-down switching regulator featuring the LT3480 in the MSOP-10 exposed pad package. The operating frequency can be synchronized up to 2MHz. The demo board is designed for 5V/2A output from a 6.3V to 38V input with transients up to 60V. The wide input range of the LT3480 allows a variety of input sources. The typical sources are automotive batteries, wall adaptors and industrial supplies. The modes of operation (Burst Mode and fixed frequency) are jumper selectable.
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.