Re: Op-amp design: Bipolar or Cmos

linnix wrote:

On Jun 8, 11:34 am, Joerg <notthisjoerg...@xxxxxxxxxxxxxxxxxxxxx>
wrote:

linnix wrote:

On Jun 8, 7:16 am, Rene Tschaggelar <n...@xxxxxxxx> wrote:

Jim Thompson wrote:

Are you saying you need an 18V OpAmp? That arrows you down to just a
couple of foundries in the WORLD. As you've already been advised...
get thee hence to a foundry.

...Jim Thompson

Jim,
You are saying CMOS OpAmps are limited to supply voltages
below 18V ? Amazing. I wasn't aware of that. Standard
bipolar OpAmps extend to the double.

Rene

Anyone making 4000-series CMOS anymore? If they are do they do
foundry work? I'm talking _practical_ here not theoretical.

For a high voltage OpAmp in bipolar (or CMOS for that matter),
features sizes and chip dimensions get enormous!

If you've got the bucks I can give you anything you want ;-)

...Jim Thompson

Thanks Jim,
for the slow learners : The voltages defines
the insulation thickness, and a thicker insulation
is to be compensated with area to get the same
capacitance. Since the insulation thickness is
linear to the voltage, as the area is to the capacitance,
IMO, the area should scale linear with the voltage.
Meaning double the voltage, and the area is also doubled.

Sounds reasonable. No ?

Without saying too much to break my NDA with the fab, the target
voltage is 15V. So, no point in going more than 18V to 20V.

18V would be a white-knuckle ride IMHO. 20V, maybe.


OK, we will probably boost from 6V (batteries) to 24V and regulate it
down to 20V. The device is a second order closed loop system with
damping, using op amp integrations on MEMS. Any more descriptions
will need a 5 years NDA! After that, you can write a book if you
wish.


I just wouldn't do that on a 20V process. Bzzt ... poof ;-)

--
Regards, Joerg

http://www.analogconsultants.com
.

Relevant Pages

  • Re: Op-amp design: Bipolar or Cmos
    ... get thee hence to a foundry. ... You are saying CMOS OpAmps are limited to supply voltages ... linear to the voltage, as the area is to the capacitance, ... the area should scale linear with the voltage. ...
    (sci.electronics.design)
  • Re: Op-amp design: Bipolar or Cmos
    ... get thee hence to a foundry. ... You are saying CMOS OpAmps are limited to supply voltages ... Since the insulation thickness is ... the area should scale linear with the voltage. ...
    (sci.electronics.design)
  • Re: Op-amp design: Bipolar or Cmos
    ... get thee hence to a foundry. ... You are saying CMOS OpAmps are limited to supply voltages ... Since the insulation thickness is ... the area should scale linear with the voltage. ...
    (sci.electronics.design)
  • Re: Op-amp design: Bipolar or Cmos
    ... get thee hence to a foundry. ... You are saying CMOS OpAmps are limited to supply voltages ... Since the insulation thickness is ... the area should scale linear with the voltage. ...
    (sci.electronics.design)
  • Re: Op-amp design: Bipolar or Cmos
    ... get thee hence to a foundry. ... Since the insulation thickness is ... the area should scale linear with the voltage. ...
    (sci.electronics.design)
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