hello,
looks so huge, why did you chosen such huge one, any special purpose?

Is your architecture is one opamp with pmos pass transistor or any thing else?

Thanks,
Raj.

i guess pmos input is Quite high, try to increase Vgs rather increasing width, this can be done by redesigning opamp output common mode.

Show me your ckt....

Thanks,
Raj.

Your power transistor is going to be broken up into multiple parallel devices, general by using "multiple fingers"

(often "NF=xx parameter on the transistor)

Cautions:

Get a rough estimate of the gate resistance (not in transistor model)
and make sure that the Cgs, Cgd, Cgate-elsewhere do not play into an
RC constant along the gate of the long gate stripe that is the W of the transistor.

That may limit the max W that you use in the transistor.

Connect the gate driver circuit to both ends of the gate stripe.

Also, the NF number may be limited by how far apart you can space the NWell contacts.
A large NF and a large W leads to a large NWell under the transistor. Check the design rules for
how large you can make the NWell.

That may require use of "M=" for multiple devices where devices are separated by well contacts.


Balance the resistive metal paths from each part of the transistor
so the IR drops balance and give equal current density
in the transistor.

That's what I can immediately think of.

hello grosser ,
Is it posb to extract this structure, because it is not an standard pcell, that's why i am asking.

Thanks,
Raj.

Why not push the power transistor off chip?  Power Qs are cheap and at the size you are talking about it may begin to make sense.

If you can't do that you are stuck doing a custom layout. There are numerous issues including latch up, ESD, thermal, metal migration, yield, modeling, parasitic thyristors, etc.

If you don't understand all of these issues and mitigate the risks you will get burned.

I have seen some guys use multiple voltage regulators in parallel to make the stability a little easier.  I also saw one person put a switch mode supply in parallel with an LDO.

I have also seen a few papers about using the gate RC as part of the stability.

For all things linear regulator check out Rincon-Mora's work.