Re: CMOS analogues switch capacitance

On Thu, 19 Oct 2006 16:34:42 GMT, Joerg
<notthisjoergsch@xxxxxxxxxxxxxxxxxxxxx> wrote:

Hello Joseph,


There is another issue with CMOS switches operating in low noise or high
speed applications. It is not really like capacitance but produces similar
effects, it is charge injection. Charge injection is relatively free of
temperature effects, but varies some with input voltage and supply voltage.
Have you had to design to control it?


I guess anybody who ever designed samplers has. It's not always fun
though, especially when you find out like I did a few years ago that
your favorite quad array has been priced out of the typical BOM budget
range :-(

However, there is another architecture that seems to not be taught
anymore at the colleges: Four fast diodes and a toroid transformer.
Ideally a quad but many of those have become expensive/unobtainium so I
usually try to get away with pairs. That reduces Ci effects down to
almost zilch.

Hard to integrate though ;-)

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
.

Relevant Pages

  • Re: CMOS analogues switch capacitance
    ... effects, it is charge injection. ... I guess anybody who ever designed samplers has. ... especially when you find out like I did a few years ago that your favorite quad array has been priced out of the typical BOM budget range :-( ... there is another architecture that seems to not be taught anymore at the colleges: Four fast diodes and a toroid transformer. ...
    (sci.electronics.design)
  • Re: CMOS analogues switch capacitance
    ... effects, it is charge injection. ... but varies some with input voltage and supply voltage. ... I guess anybody who ever designed samplers has. ... especially when you find out like I did a few years ago that your favorite quad array has been priced out of the typical BOM budget range :-( ...
    (sci.electronics.design)