Linear Technology Corp. (LTC, Milpitas, CA) announces its new LT3477, a current-mode, fixed-frequency dc-dc converter with dual rail-to-rail current sense amplifiers and an internal 3 A, 42 V switch. The LT3477 operates from an input-voltage range of 2.5 V to 25 V, making it suitable for a wide variety of applications. It combines a traditional voltage feedback loop and two current feedback loops to operate as a constant current and a constant voltage source that is suitable for driving high-current LEDs.
Both inputs of the error amplifier are available to the user, allowing the LT3477 to be used as either a boost converter, SEPIC or an inverter. It can also be configured as a buck-boost mode or buck-mode LED driver, enabling it to operate in a wide array of applications, even those with fluctuating voltage inputs such as an automotive battery. The LT3477's low VCESAT Switch, 0.3 V at 2.5 A, operates at efficiencies of up to 91%. The low-profile (0.75 mm) 4 mm x 4 mm QFN-20 package provides thermal performance in a small footprint. The LT3477 is also available in a thermally enhanced, 20-pin TSSOP package.
The LT3477EUF (4 mm x 4 mm, QFN-20 version) and the LT3477EFE (TSSOP-16E version) are available from stock. Pricing for the LT3477EUF starts at $3.15 each and $3.30 each for the LT3477EFE, both in 1,000-piece quantities.