Milpitas, Calif.—Linear Technology's LT3825 is a synchronous flyback DC/DC controller for 10-60 watt, or up to 12-amp, isolated power supplies. The design touts superior thermal performance at high output currents, a much simpler approach compared to forward converters applied in a lower power application, and sets claim to boosting power supply efficiency by 3-5 percent.
This current-mode controller uses a feedback amplifier in the sensing loop that eliminates the need for the usual optoisolator, thus providing tighter regulation and faster dynamic response. The chip's synchronous rectifier topology increases conversion efficiency and improves output cross regulation in multiple output power supplies. Thus, for example, the LT3825 can transform a 36-72 input to an isolated 3.3-volt output at 12 amps with up to 90% efficiency and 0.005 percent (typical, 0.02 percent worst case) regulation for telecom, medical, industrial and instrumentation systems.
A programmable primary gate delay function serves in place of multiple discrete (external) components and optimizes MOSFET switching time and transformer selection. To further simplify the design, the LT3825's switching frequency is adjustable (using a capacitor) from 50 to 250 kHz. The IC can also be synchronized to an external oscillator.
Click here for the datasheet. The LT3825, rated for operation from -40 to +125°C, is offered in a thermally enhanced 16-lead TSSOP. It's priced at $3.10 each in 1k pieces.
Linear Technology, 1-800-4LINEAR, www.linear.com