New Industry Products

Linear Tech Ideal Diode Controller Integrates 5A MOSFET To Replace Lossy Schottky Diodes

August 03, 2008 by Jeff Shepard

Linear Technology announced the LTC4358, a single high voltage ideal diode controller utilizing an internal 5A MOSFET to provide a simple, low loss replacement to Schottky diodes in high current applications. The controller and 20mΩ internal N-channel MOSFET perform the function of a low forward voltage diode. This provides a lower loss path compared to the Schottky diode that in high current applications provides higher efficiency and preserves precious board area by eliminating the need for heat sinking.

Linear states that the LTC4358 regulates the forward voltage drop across the internal MOSFET to ensure smooth switchover from one path to another without oscillation. A fast pull-down circuit minimizes reverse current transients in the event a power supply fails or is shorted. It is stated that the LTC4358 can be viewed as a three terminal diode for general purpose applications such as reverse battery protection in automotive applications, or ORing power supplies together in applications that demand high system reliability.

The LTC4358 single ideal diode controller is useful in applications where multiple, redundant power supplies are paralleled to provide load sharing. In N+1 redundant systems, the LTC4358 provides a convenient method to OR together an additional supply to safeguard the system in the event one of the N supplies fail. This ORing technique provides necessary isolation for live insertion and removal of converters onto the power bus and to provide isolation from the bus during a hard short. If the power source fails or is shorted, the LTC4358 ensures a fast 500ns turn-off to minimize reverse current transients.

Specified over the commercial and industrial temperature ranges, the LTC4358 is offered in 4 x 3mm 14-pin DFN and 16-lead TSSOP packages. Pricing begins at $2.10 each in 1,000 piece quantities.