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Industry’s first 250V silicon Schottky for plasma/LCD TV, power supply applications

New 200-250 V Schottky's outperform traditional Ultrafast rectifiers – eliminating noise at all temps, minimizing EMI filtering requirements, improving circuit efficiency and delivering superior reverse recovery and high stability

Power Electronics Technology Conference (PET) ” Chicago, IL — A leading industry supplier of power discrete components, ON Semiconductor pushed the Schottky voltage barrier above 200 volts (V) with the introduction of the first 250 V silicon Schottky for plasma/LCD television, power supply, consumer and automotive applications. Further expanding its high voltage Schottky portfolio, the company also introduced two new 200 V Schottky rectifiers in SMC packages.

The quiet operation and fast recovery time of ON Semiconductor's new 200 V and 250 V Schottky's outperform Ultrafast rectifiers reverse recovery time, forward voltage and softness. As such, the new high voltage Schottky devices simplify system design and offer a more cost-effective solution for the growing number of 200-250 V applications ” including plasma television drive circuits, automotive body electronics and computer power supplies.

“Since first extending the Schottky voltage boundary to 200 V in the early 1990s, ON Semiconductor has remained the high voltage silicon Schottky leader,” said Keith Nootbaar, ON Semiconductor director of the Power Discrete products. “While our competitors are only now beginning to reach 200 V, ON Semiconductor has set a new industry milestone of 250 V and has plans to continue upward development of the technology in the future.”

High Voltage Schottky vs Ultrafast Rectifiers
Traditionally, Ultrafast rectifiers have been used for energy recovery, fly-back surge and output rectification in applications where the reverse voltage can exceed 200 V. An example of a key application is energy recovery circuits for plasma TV panels. In this application, switching frequencies are on the order of 250 kHz and voltages run greater than 180 V peak-to-peak. This necessitates a low forward drop rectifier with the best possible switching. The energy recovery rectifiers should have a minimum breakdown voltage on the order of 250 V (allowing for derating and spikes). Ultrafast rectifiers have traditionally been used in this application, but with advanced silicon Schottky technology ON Semiconductor has developed a better solution.

“The 250 V breakdown was previously beyond the performance range of commercially available silicon Schottky rectifiers,” said Nootbaar. “A designer was left with a choice between standard Ultrafast, soft recovery Ultrafast or expensive alternatives such as silicon carbide. Using advanced silicon Schottky technology, ON Semiconductor has achieved lower forward voltage (Vf < 1.0) and addressed both the switching loss and electromagnetic interference (EMI) issues that are also significant at these (200-250 kHz) frequencies."

The new devices introduced by ON Semiconductor to expand their existing 200 V and above rectifier portfolio are:
* MBR40250: 40 Amp, 250 V Schottky offered in a T0-220 package and die
* MBRS4201: 4 Amp, 200 V Schottky offered in a SMC package.
* MBRS3201: 3 Amp, 200 V Schottky offered in a SMC package.

These new high voltage Schottky devices eliminate reverse recovery oscillations present in Ultrafast rectifiers at all temperatures. Because oscillations (noise) are the main cause for EMI, the new 250 V Schottky technology eliminates the need for EMI filtering ” and with it the costs of EMI filtering. In comparison, Ultrafast rectifiers used in high temperature applications show increased reverse recovery oscillations. This increases EMI and adds filtering costs to the overall system design.

The softness factor (tb/ta) of these 200 V and 250 V Schottky devices also significantly outperforms Ultrafast rectifiers. The superior reverse recovery time (tRR) and high stability of the Schottky at hot temperatures compared to similar voltage Ultrfast Rectifier reduces switching losses in rectifier applications, improving the overall efficiency of the circuit.

The new devices are priced between $0.30 and $1.00 per unit in 10,000-unit quantities. For more information visit ON Semiconductor's web site at www.onsemi.com.

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