Window comparator bypass cap values?

[Bill Bowden]

Are bypass caps needed on the reference inputs to a window comparator?
If so, what values are recommended?

Typical example here (with no caps):

http://home.cogeco.ca/~rpaisley4/ComparatorWindow.GIF

-Bill

 

[Tom Biasi]

On Sun, 1 Apr 2012 19:48:06 -0700 (PDT), Bill Bowden
<bperryb@bowdenshobbycircuits.info> wrote:

Are bypass caps needed on the reference inputs to a window comparator?
If so, what values are recommended?

Typical example here (with no caps):

http://home.cogeco.ca/~rpaisley4/ComparatorWindow.GIF

-Bill

I have never used any.

Tom

 

[Jim Thompson]

On Tue, 03 Apr 2012 16:17:35 -0400, Tom Biasi <tombiasi@optonline.net>
wrote:

On Sun, 1 Apr 2012 19:48:06 -0700 (PDT), Bill Bowden
bperryb@bowdenshobbycircuits.info> wrote:

Are bypass caps needed on the reference inputs to a window comparator?
If so, what values are recommended?

Typical example here (with no caps):

http://home.cogeco.ca/~rpaisley4/ComparatorWindow.GIF

-Bill

I have never used any.

Tom

Depends on the rise and fall time of the input, _and_ the comparator.
Sufficiently fast edges and a crappy comparator could couple input to
references. I tend toward bypassing.

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

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

 

[Tom Biasi]

On Tue, 03 Apr 2012 13:38:52 -0700, Jim Thompson
<To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> wrote:

On Tue, 03 Apr 2012 16:17:35 -0400, Tom Biasi <tombiasi@optonline.net
wrote:

On Sun, 1 Apr 2012 19:48:06 -0700 (PDT), Bill Bowden
bperryb@bowdenshobbycircuits.info> wrote:

Are bypass caps needed on the reference inputs to a window comparator?
If so, what values are recommended?

Typical example here (with no caps):

http://home.cogeco.ca/~rpaisley4/ComparatorWindow.GIF

-Bill

I have never used any.

Tom

Depends on the rise and fall time of the input, _and_ the comparator.
Sufficiently fast edges and a crappy comparator could couple input to
references. I tend toward bypassing.

...Jim Thompson

OK, I never had a problem but restricted design to clean DC.
I agree with your statement.

Tom

 

[George Herold]

On Apr 1, 10:48 pm, Bill Bowden <bper...@bowdenshobbycircuits.info>
wrote:

Are bypass caps needed on the reference inputs to a window comparator?
If so, what values are recommended?

Typical example here (with no caps):

http://home.cogeco.ca/~rpaisley4/ComparatorWindow.GIF

-Bill

If the reference is coming from the power rail directly (as shown in
schematic) then I'd add some bypass... no sense having PS stuff on the
reference. I'd pick an RC time of 1ms or so, (depending on what stuff
was on the supply line.)

George H.