Dual Ideal Diode Controller Replaces Two Schottky Diodes

The LTC4353 dual ideal diode controller has been designed by Linear Technology to replace two high power Schottky diodes, thereby enabling low loss ORing of multiple power sources with minimal disturbance to supply voltages. The controller regulates the forward voltage drop across external N-channel MOSFETs to ensure smooth current transfer between supplies in diode-OR applications. A <1 µs turn-on time ensures smooth switchover from one path to the other without oscillation. The controller finds use as a diode replacement in supply holdup applications where momentary collapse of supply voltage is isolated from the load. The LTC4353 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 unit consumes 75 µA per supply. Operating with supplies from 2.9 V to 18 V, the controller can control voltages down to 0 V by applying an external supply. Pricing for the LTC4353 diode controller starts at $3.45 each/1,000. LINEAR TECHNOLOGY CORPORATION