TrenchFET Gen III MOSFETs Provide Leading Performance and Energy Savings for DC-to-DC Applications

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Vishay Siliconix has released its first 30V TrenchFET Gen III MOSFETs, which improve performance in DC-to-DC applications in computers and power modules.

The enhanced performance of the MOSFETs improves efficiency at light loads, which reduces power loss during a computer's normal operation. The MOSFETs also improve efficiency at heavy loads where designs are most thermally challenged to keep the power stage runner cooler.

Vishay’s TrenchFET Gen III technology offers not only a reduction in R_DS(on) to reduce conduction losses attributed to the low side MOSFET in a synchronous buck converter, but also Q_G(TOT) to reduce switching losses attributed to the high side MOSFET. Compared to the previous generation technology, R_DS(on) @ 10V improved by 20% and R_DS(on) @ 4.5V by 30%. Total gate charge improved by 10%. The combined reduction results in a Figure of Merit (FOM) improvement at 4.5V of 38%, leading to the enhanced performance of the device in switching circuits.

The leading 30V device in the portfolio is the SI7192DP, which has an R_DS(on) of 2.25mΩ max. @ 4.5V, giving it the lowest rating in the industry for a 30V/20V MOSFET. Combined with the high side counterpart, SIR402DP, the pair provides an excellent solution for high current DC-to-DC applications converting 12V down to 3.3V and lower.

In addition, the 30V Gen III MOSFETs have been released in the 3x3mm PowerPAK1212-8 package. The lowest R_DS(on) product in the family is SIS402DN which is rated at 6mOhm MAX @ 10V with a gate charge of 12 nC TYP @ 4.5V. When this part is used as a low side switch in a buck converter along with its high side counterpart, SI7716ADN which is rated at 13.5 mOhm MAX @ 10V, it provides an excellent solution to increase performance and save space for up to 10A loads. SI7716ADN is also the recommend replacement for SI7806ADN. It offers a figure of merit reduction at 4.5V of 43%. The efficiency chart below illustrates the performance improvement of the Gen III technology compared to similar parts in PowerPAK1212-8 using the previous generation technology. Performance improved at both light loads and heavy loads leading to increased power savings. PowerPAK1212-8 also offers a board space savings of 70% compared to SO8 style packages to reduce the total area consumed by the power stage.

Vishay will be extending its Gen III technology to 20V, 25V, and 40V to cover all of the lower voltage ratings. By moving to voltages lower than 30V, the technology yields a nice figure of merit improvement which can also help optimize efficiency across the load range. Two parts are currently available, SIR890DP at 20V and SIR892DP at 25V, both in the 3 mOhm range @ 10V, which are excellent low side switches for high current buck converters.

Applications include high current voltage regulators in point-of-load modules, VRMs, servers and notebook computers. Vishay plans to release a range of R_DS(on) specs in a variety of packages to suit the needs of power engineers who face the challenge of increasing power densities and lowering power losses. As the demand to save energy by boosting efficiency in computing and fixed telecom systems increases, TrenchFET Gen III technology provides power engineers the option to use the best MOSFETs possible.

 

APPLICATIONS High current voltage regulators in point-of-load modules VRMs Servers Notebook computers

 

 

SIS402DN and SI7716ADN performance in a buck converter to 12A

SI7192DP performance comparison as low side switch in buck converter

 

 

 Featured Products

Part Number		Description	Data Sheet	App. Notes
SI4126DY-T1-GE3		N-Channel 30V (D-S) MOSFET
SI7192DP-T1-GE3		N-Channel 30V (D-S) MOSFET
SI7658ADP-T1-GE3		N-Channel 30V (D-S) MOSFET
SI7716ADN-T1-GE3		N-Channel 30V (D-S) MOSFET
SIR402DP-T1-GE3		N-Channel 30V (D-S) MOSFET
SIR890DP-T1-GE3		N-Channel 20V (D-S) MOSFET
SIR892DP-T1-GE3		N-Channel 25V (D-S) MOSFET
SIS402DN-T1-GE3		N-Channel 30V (D-S) MOSFET

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