Safe Operating Area of DPAK FETs is so different...why?

[treez]

Hi,
The SPD03N60C3 and the IPD70R900P7S are both DPAK FETs of around the same voltage rating.

However, the SPD03N60C3 has a far better Safe Operating Area performance.

SPD03N60C3 can handle 200V for 1ms at 350mA
However, the IPD70R900P7S can handle 200V for 1ms at no more than 50mA.

Do you know why these FETs differ so much in their SOA's?….i mean, their other parameters are very similar, and they are in the same DPAK package.

SPD03N60C3 datasheet
https://www.infineon.com/dgdl/SPD03N60C3_rev+2+6.pdf?fileId=db3a3043191a246301192907f3b27f4b

IPD70R900P7S datasheet
https://www.infineon.com/dgdl/Infin...N.pdf?fileId=5546d462584d1d4a0158cf8102e90d98

 

[Easy peasy]

different die sizes - this is also reflected on the Rth,j-c

 

[FvM]

You find the answer if you read the SOA curves thoroughly.

The chip areas are almost similar, indicated by the low voltage (e.g. Vds = 20V) pulse rating. C7 "superjunction" family has however considerable pulse energy derating for Id < 1A, I guess due to inhomogeneous current distribution.