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New H-Type Schottky Rectifiers Feature Forward Voltage Drop as Low as 0.49 V, Leakage Current Down to 3.0 mA, and Operating Junction Temperatures up to 175°C

The manufacturer says...

Chipcenter's Nasser Kutkut, Ph.D., says...

Vishay Intertechnology, Inc. released the first products in a new rectifier series using a breakthrough technology that combines low forward voltage, low leakage current, and a high maximum operating junction temperature. Devices in Vishay's new H-type high-barrier-height family of rectifiers are built on a proprietary Schottky-barrier technology that allows for a typical forward-voltage drop as low as 0.49 V, typical leakage current as low as 2.0 mA at 125°C, and a high maximum operating junction temperature of 175°C. Additional reliability is provided with an excellent reverse-surge capability of 25 kV ESD and minimum inductive reverse-avalanche energy up to 80 mJ. The specifications for the new Vishay Semiconductors devices represent an order of magnitude improvement over previous-generation Schottky rectifiers, with the leakage current reduced by as much as 90% and the forward-voltage drop by as much as 18%. The new devices will be used to provide low-loss operation in high-frequency DC/DC conversion, high-frequency inversion, SMPS, and polarity-protection applications. Typical end products will include power supplies, battery chargers, desktop computers, servers, set-top boxes, LCD monitors, plasma displays, projectors, printers, lamp ballasts, and telecom power systems. The only way to achieve low leakage current and a high operating temperature in a Schottky rectifier is to increase the barrier height. But with previous-generation technologies, the effect of the higher barrier height was to worsen forward-voltage drop performance. Vishay's proprietary Schottky barrier technology overcomes this trade-off by optimizing the design to take advantage of a phenomenon known as conductivity modulation. The result is a device that combines low leakage current, a high operating temperature, and low forward-voltage drops—allowing efficient operation with low losses even during high-frequency and high-temperature operation. H-type Schottky rectifiers are available in eight forward-current options ranging from 7.5 A up to 40 A with 35 V to 45 V and 50 V to 60 V reverse-voltage options. The devices' metal-silicon junction is built using a proprietary sputtering process that guarantees a well-controlled barrier height. The resulting majority-carrier conduction causes a forward-voltage drop that is lower than a p-n junction rectifier, with negligible reverse-recovery time. An ion-implanted guard-ring technology provides an excellent reverse-energy capability, thereby ensuring overvoltage protection. Single- and dual-rectifier configurations are included within the H-type device family, which is available to designers in six package outlines: TO-220AC, TO-220AB, ITO-220AC, ITO-220AB, ITO-263AB, and TO-247AD. Samples and production quantities of the new H-type high-barrier-height Schottky rectifiers are available now, with lead times of four weeks for larger orders.

Schottky diodes' design parameters include a number of variables that cannot be optimized simultaneously. Finding Schottkys with low voltage drops, low leakage currents at higher temperatures, and high operating junction temperatures is a challenge. In particular, the Schottky's reverse leakage current at higher temperatures can be relatively high, and results in additional losses within the device, which may lead to failure. Well, this may not be the case anymore. A new breakthrough Schottky technology from Vishay is poised to offer a low forward drop with very low leakage currents at high temperatures. The new H-Type Schottky rectifiers offer forward-voltage drops as low as 0.49 V and typical leakage currents as low as 2 mA, making them the lowest in the industry. The new series is available in voltages up to 60 V and currents up to 40 A.

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