What knowledge of semiconductor devices, their
construction and electronic physics do you already
have? Can you recognize a lateral bipolar transistor
if you see one? Can you draw from memory the
structure you are asking questions about? Give it
a try, hand and eye, and maybe dig for some
information on base width vs breakdown (with a
sweet bipolar gain assist, and a possibility that it's
half of a SCR that won't turn off on its own).
Look at your technology's VPNP device, and say
your LNPN had better have its reciprocal or less.
What base width does it take to make this true?
Any less and you'd best have some really dense
shunt conductance (sub and well taps) and this
is leaving yourself open to a design or rules "miss".