Close

Decoupling

A project log for DYPLED

a thin LED display in SIP module format, much better than TIL311s to visualise your computer buses

yann-guidon-ygdesYann Guidon / YGDES • 02/10/2017 at 18:23•4 Comments

Franck just spotted a pretty fumble : I have overlooked the bulk capacitors before and after the LP2981.

I think I assumed that the voltage stability was not critical but usually I am very generous with capacitors.

The other problem is : is there any room left ?
Previous log

Resuming

11/17/2016 at 15:30 • 0 comments
Next log

PCB rev.2

04/24/2017 at 12:16 • 0 comments

Discussions

K.C. Lee wrote 02/10/2017 at 18:40 • point

You can replace all the 0.1uF decoupling caps with 1uF ceramic caps as a way to increase the bulk value.   Leave the 0.1uF in if there are any high speed chips.

For low frequency work (as in the 10-20MHz or below), it won't make much of a difference.

  Are you sure? yes | no

K.C. Lee wrote 02/11/2017 at 22:50 • point

Sorry gave you bad advice.  Turns out that the LP2981 doesn't like ceramic caps because of their low ESR.  So you might have to find some small tantalum/electrolytic caps for the output bulk caps.

  Are you sure? yes | no

Yann Guidon / YGDES wrote 02/12/2017 at 00:42 • point

I supposed so, thanks for confirming ! I'm running out of space...

  Are you sure? yes | no

K.C. Lee wrote 02/12/2017 at 04:13 • point

The pin out of LP2981 is the same as Microchip MIC5245 which is compatible with ceramic caps.  There might be other parts that are compatible too.

  Are you sure? yes | no

Yes, delete it Cancel

Going up?

About Us Contact Hackaday.io Give Feedback Terms of Use Privacy Policy Hackaday API

© 2024 Hackaday