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Robust, Fault-Tolerant OR-ing MOSFET Controller has Ultra-Fast 200ns MOSFET Turn-Off
SUNNYVALE, CA-April 7, 2005-Maxim Integrated Products (NASDAQ: MXIM) introduces the MAX5079 OR-ing MOSFET controller. The MAX5079 replaces bulky and high-power-dissipation OR-ing diodes with low-voltage-drop, n-channel MOSFETs in high-current parallel, redundant power supplies. The device is specifically designed to meet the stringent requirements for redundant power supplies in servers, RAID, networking, switch/routers, and silver boxes.
The MAX5079 has an input OR-ing voltage range of 2.75V to 13.2V. An impressive 1V-to-13.2V input-voltage range is achievable if an auxiliary bias voltage of 2.75V or greater is available to bias the device.
The device provides the most robust level of fault tolerance required by high-reliability systems. The MAX5079 takes power from VBUS or an auxiliary power, if present, to quickly turn off the OR-ing MOSFET when VIN fails, and thereby effectively isolates the bus from the faulty power supply. In addition, the device detects and reports supply undervoltage and bus overvoltage conditions. During a fault condition when VIN drops below VBUS, the MAX5079 turns off the external MOSFET with up to 3A gate pulldown current, thus providing ultra-fast 200ns turn-off time. This action prevents VBUS from being pulled down and maintains the integrity of the main power bus, even during catastrophic fault conditions. An adjustable reverse-voltage threshold, moreover, eliminates nuisance trips due to glitches at VBUS. An additional slow comparator with adjustable threshold and blanking time eliminates nuisance trips during hot-plugging parallel power supplies.
The MAX5079 operates over the -40°C to +85°C extended temperature range and is available in a space-saving 5mm x 6.5mm, 14-pin TSSOP package. Prices start at $1.15 (1000-up, FOB USA).
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