Junior Member level 3
in order to prevent Psub-nwell diode forward conduct when voltage is negetive , a iso-nmos is used. now the problem is whether two nmos may oxide rupture,
the process has BDVds>12V, but Tox is 150A, so Vgs<5V to avoid oxide rupture.
but for my schematic configuration, Vgs(Vgd) some time exceed 5V.