DC/DC controller targets industrial applications

The LT3748 from Linear Technology is a high-input-voltage isolated flyback DC/DC controller that is suitable for a range of industrial, medical, telecom, datacom and automotive applications.

The LT3748 is said to simplify 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 LT3748 operates over a 5V to 100V input voltage range and drives an external N-channel power Mosfet.

It operates in boundary mode, which is a variable frequency current mode control switching scheme, resulting in +/-5 per cent typical 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 easily 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.

The high level of integration and the use of boundary mode operation results in a simple, clean application solution to the traditionally tough problem of isolated power delivery, according to Linear Technology.

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

The LT3748 is available in a small MSOP-16 package with four pins removed for additional high-voltage pin spacing.

This device is available in extended and industrial operating junction temperature range at -40C to 125C.

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