MOSFETs drop gate charge and on-resistance

Two new power MOSFETs combine the extremely low gate charge values enabled by WFET technology with the very low on-resistance values of TrenchFET Gen II technology.

Two new power mosfets combine the extremely low gate charge values enabled by WFET technology with the very low on-resistance values of TrenchFET Gen II technology.

The two power mosfets are designed for low-side operation in synchronous buck (single- and multiphase configurations) DC/DC convertors in notebook PCs, servers, and VRM modules, as well as in synchronous rectification in fixed telecomms systems.

The new Si4368DY (PowerPAK SO-8) and Si7668DP (SO-8) feature on-resistance of 3.6mohm (at a 4.5V gate drive) and a low on-resistance-gate-charge value of 23mohm-nC for improvements of 25 and 54%, respectively, over specifications for competing mosfet devices.

Both devices provide an exceptionally low gate charge ratio of 0.37 - also 54% better than competing devices - to ensure high "shoot-through" immunity and to help keep gate charge in check for reduced switching losses and more efficient DC/DC convertor performance.

The maximum gate threshold voltage for the Si4368DY and Si7668DP is 1.8V.

Packaged in the thermally enhanced PowerPAK SO 8 package, the Si7668DP also offers lower thermal resistance and greater power dissipation.

Vishay's innovative WFET technology uses a thicker gate oxide at the bottom of the devices' silicon trench to reduce capacitance and gate charge with minimal impact on on-resistance performance, boosting the efficiency of DC/DC convertors.

With the release of the new devices, designers can now build an all-WFET DC/DC convertor using the Si4368DY or Si7668DP on the low side and the previously announced Si4390DY or Si7390DP on the high side.

The WFET power mosfets' low conduction and switching losses translate directly into a 2% improvement in DC/DC convertor efficiency over competing solutions in typical applications.

By applying WFET technology to its latest high-density silicon in the Si4368DY and Si7668DP, Vishay achieves a transistor density of 300 million cells per square inch and a low specific on-resistance of 12mohm/mm2 without compromising switching performance.

As a result, the new devices enable design of faster, lighter, smaller, cooler, more efficient, and longer-running products with more robust feature sets.

All WFET power mosfets are 100% Rg-tested to ensure that devices perform as specified in high-frequency DC/DC applications.

Samples and production quantities of the new WFET TrenchFET Gen II power mosfets are available now, with lead times of 10-12 weeks for larger orders.

Pricing for US delivery in 100,000-piece quantities starts at $1.25.

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