datasheets.com EBN.com EDN.com EETimes.com Embedded.com PlanetAnalog.com TechOnline.com   UBM Tech
UBM Tech
Home    Bloggers    Blogs    Article Archives    Messages    About Us   
Tw  |  Fb  |  In  |  Rss
Jonathan Harris

ADC Power Supplies: Inputs

Jonathan Harris
jonharris0
jonharris0
6/9/2014 10:30:30 AM
User Rank
Blogger
Re: Starting supplies - requirements
Another good point.  I discussed a little about PSRR back in my December blog: http://www.planetanalog.com/author.asp?section_id=3041&doc_id=562140

I'll be continuing to look at power supply schemes in my upcoming blog and try to point out some topologies and strategies to help mitigate any issues from power supply noise.  Stay tuned! :-)

Thanks for both of these great questions/comments!

50%
50%
jonharris0
jonharris0
6/9/2014 10:26:24 AM
User Rank
Blogger
Re: avoiding crosstalk
That is a very good question.  Unfortunately, those are internal design details.  Care is taken inside the ADC to minimize crosstalk and part of this is to separate the supply domains at the pins of the device.  As you have pointed out there are also frequency relationships inside the ADC that must be evaluated...but those are part of the 'secret sauce' inside the device. :-)

50%
50%
etnapowers
etnapowers
6/3/2014 11:25:53 AM
User Rank
Newbie
avoiding crosstalk
"There are various portions of circuitry within each of these blocks that operate at different frequencies, and keeping the supply domains separate helps keep these frequencies from making their way back and forth between the two sections. Having crosstalk between these sections can result in degraded performance, which may manifest itself in the SNR (noise performance) or the SFDR (spurious performance) of the ADC."

 

I wonder if there is a guideline to establish the minimum value of difference between the frequencies that prevents crosstalk, which affects the performances of the ADC.

50%
50%
RedDerek
RedDerek
6/2/2014 11:18:43 AM
User Rank
Master
Starting supplies - requirements
Best place to start, besides voltage levels, is allowed ripple on the supply. This would then be the PSRR. And thus can affect how the supply is designed - frequency for one. Is is always best to use a high frequency power supply? Challenges here is that the dynamic range of output power is reduced at higher frequencies. (I ask these questions only to get the conversation started.)

50%
50%
More Blogs from Jonathan Harris
Keeping the power supply inputs on separate domains can minimize crosstalk and make it much harder for noise to interfere with ADC performance.
As is typically the case, at least from my observance in the last four years, the second day of the show proved to be the busiest.
After a good first two days and very enjoyable evenings of the IMS show, it was time for the last day, when traffic is typically good in the morning but tapers off as the day moves toward lunch and beyond.
After a very eventful preparation and buildup to the IMS show this year, Ill have to admit I was hoping for a smooth and uneventful show -- meaning no surprises resulting in something going wrong in the demonstration booth.
Once again I thought I'd do a series of blogs on my experiences as an applications engineer for a major semiconductor company, Analog Devices, at International Microwave Symposium (IMS).
flash poll
educational resources
 
follow Planet Analog on Twitter
Planet Analog Twitter Feed
like us on facebook
our partners
Planet Analog
About Us     Contact Us     Help     Register     Twitter     Facebook     RSS