**Part Number:**LM74701-Q1

Hello,

A customer wants to know a bit more details of the datasheet explanation.

In 9.2.2.2 MOSFET Selection of the datasheet, I think there are 2 estimations as listed below. Would you please explain a bit more details about them?

**1.** The resulting average current (IISO_AVG) can be approximated as __one third__ of the peak current that is around 2.4 A.

Is the approximation of “one third” made as a graphical approximation? Namely, since the yellow area below is in appearance roughly 1/3 of the rectangle of 7A x 1ms, the average current for 1ms is 2.4A? Although the actual calculation is 2.33333A and even if 2.3A is closer? Or is there another calculation?

**2.** Selecting a MOSFET with SOA characteristics covering the load line of 43 V which can support drain current greater than __(I____ISO_PEAK____/2)__ for 1 msec is a good starting point.

Is the denominator of 2 in (IISO_PEAK/2) based on an assumption of the current never go below the blue line in the below figure? Namely, the actual current will be always above the blue line such as the green line? Or is there another reason for the “2”?

Another question is, where did the -100V and 1ms come from? The customer seems to think 150V for 2ms should be more common. What is the reference?

Thank you.

Regards,

Oguri (TIJ atuomotive FAE)