Linear Technology LT3575 flyback switching regulator

Linear Technology has released the LT3575, an isolated monolithic flyback switching regulator that simplifies the design of an isolated DC/DC converter.

No opto-isolator, third winding or signal transformer is required for feedback since the output voltage is sensed from the primary-side flyback signal. The device operates over a 3 to 40 V input range, has a 2.5 A power switch and delivers up to 14 W, making it suitable for a wide variety of industrial, medical, telecom, datacom and motor vehicle applications.

The regulator operates in boundary mode, which is a variable frequency current-mode control switching scheme, typically resulting in ±5% regulation over the full line, load and temperature range. Boundary mode also permits the use of a smaller transformer compared with equivalent continuous conduction-mode designs.

The output voltage is set by two external resistors and the transformer turns ratio. Several off-the-shelf transformers, identified in the data sheet, can be used for numerous applications.

Additional features include an onboard low dropout regulator for IC power, programmable soft-start, undervoltage lockout, adjustable current limit and output voltage temperature compensation.