MOSFET Diode OR Controller suits redundant power supplies.
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Press Release Summary:
Available in 10-Pin MSOP, model LT4351 allows for low loss ORing of multiple power sources with minimal effect on supply voltages. Product uses N-channel MOSFET as pass element, turned on when power is applied and off when input source voltage drops below output common supply voltage. Features include internal boost regulator, STATUS pin, under/overvoltage monitoring, and FAULT##CRLF# pin. Operating voltage range allows for ORing of supplies from 1.2-18 V.
Original Press Release:
MOSFET Diode-OR Controller Eliminates Dissipation in Redundant Power Supply Applications
MILPITAS, CA - January 28, 2004 - 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 ORing 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##CRLF# pin to indicate when the input supply is outside of proper levels. A wide operating voltage range allows for ORing 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 ORing 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
Company Background
Linear Technology Corporation was founded in 1981 as a manufacturer of high performance linear integrated circuits. Linear Technology products include operational, instrumentation and audio amplifiers; voltage regulators,power management devices, DC-DC converters and voltage references; comparators; monolithic filters; communications interface circuits; one-chip data acquisition sub-systems; pulse-width modulators and sample-and-hold devices; and high frequencydevices. Applications for Linear Technology's high performance circuits include wireless and broadband telecommunications infrastructure, cellular telephones, networking products and satellite systems, notebook and desk top computers, computer peripherals, video/multimedia, industrial and medical instrumentation, automotive electronics, factory automation, process control, military and space systems, and high-end consumer products including digital cameras, MP3 players and other electronic products.
Note: LT, AND LTC are registered trademarks of Linear Technology Corp.
