42-V Boost Converter with Wide Input Range

Dec 1, 2004 1:47 PM
Edited by PETech Staff

The new LT3479 from Linear Technology Corp. is a current mode, fixed-frequency step-up dc-dc converter with an internal 3-A, 42-V switch. It operates from an input voltage range of 2.5 V to 24 V, making it suitable for applications with input sources ranging from a single cell Li-Ion to a 20-V wall adapter.

Both inputs of the error amplifier are available to the user, permitting use as a boost converter or an inverter. Its 42-V switch enables outputs as large as 40 V. It can also drive two high-current white LEDs (in series) with current as high as 700 mA from a single Li-Ion cell. In addition, its switching frequency can be programmed, via a single resistor, between 300 kHz and 3.5 MHz, enabling the designer to minimize external component sizes and avoid "noise critical" frequency bands in the system. A tiny/low-profile inductor and ceramic capacitors keep solution footprints compact while minimizing solution cost.

The LT3479's low V_CESAT switch, 0.3 V at 2.5 A, delivers efficiencies of up to 89%. The device features a programmable soft-start function to limit inductor current during start-up as well as inrush current protection to protect the LT3479 during shorts and line transients. The low-profile (0.75 mm) 14-pin, 4-mm × 3-mm DFN-14 package provides excellent thermal performance in a small footprint. The LT3479 is also available in a thermally enhanced 16-pin TSSOP package.

Both the LT3479EDE in a 4-mm × 3-mm DFN-14 package and the LT3479EPE TSSOP-16E version are available from stock. Pricing for both package options starts at $3.00 each for 1,000-piece quantities.

For more information, visit www.linear.com.

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