Article: Power Delivery in a Modern Processor
By: Michael S (already5chosen.delete@this.yahoo.com), May 14, 2020 12:29 pm
Room: Moderated Discussions
Ricardo B (ricardo.b.delete@this.xxxxx.xx) on May 13, 2020 11:47 pm wrote:
> Jason Creighton (asdf.delete@this.example.com) on May 13, 2020 9:09 am wrote:
> > Dan Fay (daniel.fay.delete@this.gmail.com) on May 12, 2020 9:35 am wrote:
> > > Do you know what the dropout voltage is for the on-die LDO(s)?
> >
> > I don't. You can get discrete LDOs with 100 mV or 200 mV dropouts, but I have no
> > idea what they're able to accomplish on-die in a digital-optimized process.
>
> It can go as low as 35 mV for smaller currents (100 mA).
>
> I think values for fully integrated LDO are similar.
After reading your post I asked about it one of our board designer that recently was busy developing a board with very challenging supply requirements.
He told me that linear regulators with very low drop certainly exist, but they have one big disadvantage - they poorly reject medium frequency noise (200 KHz to few MHz) when it comes from input voltage side. Only those with drop of 300 mV or more are filtering incoming ripples really well.
But, then again, he probably don't care all that much about regulators with small output current.
> Jason Creighton (asdf.delete@this.example.com) on May 13, 2020 9:09 am wrote:
> > Dan Fay (daniel.fay.delete@this.gmail.com) on May 12, 2020 9:35 am wrote:
> > > Do you know what the dropout voltage is for the on-die LDO(s)?
> >
> > I don't. You can get discrete LDOs with 100 mV or 200 mV dropouts, but I have no
> > idea what they're able to accomplish on-die in a digital-optimized process.
>
> It can go as low as 35 mV for smaller currents (100 mA).
>
> I think values for fully integrated LDO are similar.
After reading your post I asked about it one of our board designer that recently was busy developing a board with very challenging supply requirements.
He told me that linear regulators with very low drop certainly exist, but they have one big disadvantage - they poorly reject medium frequency noise (200 KHz to few MHz) when it comes from input voltage side. Only those with drop of 300 mV or more are filtering incoming ripples really well.
But, then again, he probably don't care all that much about regulators with small output current.