Linear Technology LT3748H DC/DC controller

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Linear Technology has announced the LT3748H, a high-input voltage isolated flyback DC/DC controller with guaranteed operation for junction temperatures to 150°C.

The device simplifies the design of an isolated DC/DC converter since there is no requirement for an opto-isolator, third winding or signal transformer for feedback, as the output voltage is sensed from the primary-side flyback signal. The controller operates over a 5 to 100 V input range and drives an external N-channel power MOSFET, making it suitable for a wide variety of motor vehicle, industrial, telecom and datacom applications.

The device operates in a boundary mode, current-mode control switching scheme, resulting in ±5% 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.

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