About dynamic parameter in SiC MOSFET

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WEN-YUNG
Level 3
Level 3
First like received 50 sign-ins 10 questions asked

Dear  IFXer,

I would like to discuss why dynamic parameter Ciss, Cgd, Coss, Qg, Qgd, Qds are no marking min and max value in datasheet? In all power device vendor? Thus, how to consider design in worst case?

and further question is the IMZA can co-layout with IMZ package ? if it is possible, what is our consideration in layout? 

WENYUNG_0-1678932015995.png

 

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Jingwei
Moderator
Moderator
Moderator
250 sign-ins 10 likes given 100 solutions authored

Hi WEN-YUNG,

The dynamic parameters you mentioned (Ciss, Cgd, Coss, Qg, Qgd, Qds) are typically not marked with minimum and maximum values in datasheets because their values are highly dependent on the operating conditions of the device. These parameters are typically specified as typical values or graphs that show their behavior under certain conditions, such as gate voltage, drain voltage, and temperature.

It is difficult to specify minimum and maximum values for these parameters because their values can vary significantly depending on the specific application circuit, the device packaging and layout, and the operating conditions. As a result, it is up to the designer to estimate the worst-case values for these parameters based on the specific application requirements and operating conditions.

One approach to designing with worst-case values is to use simulations to estimate the maximum and minimum values of these parameters under different operating conditions. Another approach is to use conservative estimates for these parameters and add margin to the design to ensure that it meets the required performance specifications under all operating conditions.

Best regards,

Steven

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3 Replies
Jingwei
Moderator
Moderator
Moderator
250 sign-ins 10 likes given 100 solutions authored

Hi WEN-YUNG,

The dynamic parameters you mentioned (Ciss, Cgd, Coss, Qg, Qgd, Qds) are typically not marked with minimum and maximum values in datasheets because their values are highly dependent on the operating conditions of the device. These parameters are typically specified as typical values or graphs that show their behavior under certain conditions, such as gate voltage, drain voltage, and temperature.

It is difficult to specify minimum and maximum values for these parameters because their values can vary significantly depending on the specific application circuit, the device packaging and layout, and the operating conditions. As a result, it is up to the designer to estimate the worst-case values for these parameters based on the specific application requirements and operating conditions.

One approach to designing with worst-case values is to use simulations to estimate the maximum and minimum values of these parameters under different operating conditions. Another approach is to use conservative estimates for these parameters and add margin to the design to ensure that it meets the required performance specifications under all operating conditions.

Best regards,

Steven

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Jingwei
Moderator
Moderator
Moderator
250 sign-ins 10 likes given 100 solutions authored

BTW, what you mean by co-layout?

Best regards,

Steven

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喜马拉雅之雪
Employee

不建议共用封装。

由于管脚距不同,虽然大尺寸焊盘能使它们获得名义上的兼容。但;波峰焊会导致焊锡涌孔现象。

新封装显著优化了焊盘设计,加大了栅驱动焊盘间距,减低了焊装工艺难度。推荐用新封装做新的设计;不建议兼容老封装。

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