Date: 19/06/2012

Linear releases a dual ideal diode controller replacing two Schottky diodes

Linear Technology has introduced the LTC4353, a 0V to 18V dual ideal diode controller that replaces two high power Schottky diodes, enabling low loss ORing of multiple power sources with minimal disturbance to supply voltages.

The LTC4353 controller regulates the forward voltage drop across external N-channel MOSFETs to make certain smooth current transfer between supplies in diode-OR applications. In low voltage systems, a slow handoff between controllers results in a voltage droop during supply switchover. The smooth switchover from one path to the other without oscillation is ensured by the device’s <1µs turn-on time. In the event the input supply fails or is shorted, a fast turn-off minimizes reverse current. The controller makes a diode replacement in supply holdup applications where momentary collapse of supply voltage is isolated from the load.

The device provides individual enable inputs that can be used to ensure priority to the main supply when supply voltages are within a MOSFET body diode drop of each other. With both enable inputs pulled low, the LTC4353 consumes 75µA per supply. MOSFETS on or off condition is indicated through the individual status outputs. The controller operates with supplies from 2.9V to 18V, and provides flexibility to control voltages down to 0V by applying an external supply.

The controller is available in 16-lead MSOP & DFN (4 x 3 mm) packages and is specified over the commercial and industrial temperature ranges. The price starts at $3.45 each in 1,000 piece quantities.

For more information: www.linear.com/product/LTC4353