Milpitas, Calif. - Linear Technology introduces the LT4351, an ideal MOSFET diode OR controller that allows for low loss "OR"-ing of multiple power sources with minimal effect on supply voltages. This increases total system power and reliability in network servers and N+1 redundant power supplies, while eliminating the bulky heat sink required for discrete diodes. The biggest drawback associated with conventional OR-ing diodes is power dissipation from the forward voltage drop. The LT4351 eliminates efficiency problems by using an N-channel MOSFET as the pass element. The MOSFET is turned on when power is applied, allowing for a minimal voltage drop from supply to the load. When the input source voltage drops below the output common supply voltage, the LT4351 turns off the MOSFET, thereby matching the function and performance of an ideal diode.
The LT4351 features an internal boost regulator to generate sufficient gate drive for high current MOSFETs and a STATUS pin that indicates the MOSFET on state. Furthermore, the LT4351 provides under/overvoltage monitoring and a FAULT pin to indicate when the input supply is outside of proper levels. A wide operating voltage range allows for OR-ing of supplies as low as 1.2V or up to 18V. These features make the LT4351 ideal for paralleled and redundant supplies in high-availability systems.
This elegant and efficient solution is offered in space-saving 10-pin MSOP and is specified over the commercial and industrial temperature ranges. Pricing for the LT4351 starts at $2.50 each in 1,000 piece quantities.
Summary of Features: LT4351
•Low Loss Replacement for OR-ing Diode in
Multiple Power Supply Applications
•External N-Channel MOSFETs for High-Current Capability
•Internal Boost Regulator Supply for MOSFET Gate Drive
•Wide Input Range: 1.2V to 18V
•Fast Switching MOSFET Gate Control
•Input Under and Over Voltage Detection
•STATUS and FAULT Outputs for Monitoring
•Internal MOSFET Gate Clamp
•Available in 10-Pin MSOP
READER SERVICE: Call toll-free (800)-4-LINEAR (for literature only), or go to the company's web site: www.linear.com