48-V constant on-time synchronous step-down converter targets automotive and industrial applications

March 06, 2013 // By Paul Buckley
Texas Instruments Incorporated has introduced three 48-V synchronous buck regulators with integrated high-side and low-side MOSFETs for single- and multi-output power supplies.

The 650-mA LM25017, 300-mA LM25018 and 100-mA LM25019 Fly-Buck converters feature constant on-time (COT) control architecture that reduces board space by up to 40 percent when compared with traditional designs that require multiple DC-DC converters. Used in conjunction with TI’s award-winning WEBENCH online design tool, the Fly-Buck converters simplify and speed high-voltage DC/DC designs in industrial and automotive systems.

The LM25017, LM25018 and LM25019 enable non-isolated voltage regulators and multi-output solutions from input voltages as high as 48 V. Pin-compatible LLP and PSOP packaging offers a scalable solution that covers a wide range of power requirements. Each Fly-Buck converter can be configured to provide positive and negative voltage rails, or isolated multiple outputs with excellent cross-regulation.

The Fly-Buck converters are pin-to-pin compatible with TI’s 100-V, 600-mA LM5017, 300-mA LM5018 and 100-mA LM5019 wide input voltage range regulator family. For designs that have a 3.3-V or 5-V input source and require an isolated voltage up to 2 W, TI offers the TPS55010 Fly-Buck converter with high efficiency and primary-side regulation.

The Fly-Buck converters are available in volume now from TI and its authorized distributors. Offered in thermally-enhanced 8-pin LLP and PSOP packages, the LM25017 is priced at $1.25, the LM25018 is $1.12 and the LM25018 is US$1.00 in 1,000-unit quantities. AECQ-100 qualified versions will be available in May 2013.

More information about the Fly-Buck converters at