Am Thu, 31 Aug 2017 16:08:49 +0200 hat "H. Nikolaus Schaller" hns@goldelico.com geschrieben:
Hi,
notaz mentioned the EVM has over 44 capacitors for the RAM power traces only... how many do we have and can those be changed / optimized?
We don't have that many but AFAIR there are at least 2 per DDR3 chip. On the latest (not yet populated PCB) there are 13 for 4 chips, i.e.
3 per DDR3 chip.
Ah - we optimized the capacitors for the DDR3 chips as well? Then I guess we should probably populate a few to test that!
- Basically the 4GB dual die chips may need more decoupling (local
energy buffer) for VDD because they draw more current if both chips are active
Yep.
- On the other hand 2GB RAM works well with much less decoupling than
the EVM which also has only 2GB RAM... So 48 is not needed for 2GB.
True as well. The solution is probably somewhere inbetween. As it works for Tony if he increases the voltage and Juliano showed that we might have too much noise, then a LITTLE improvement might already be enough.
So those >3 per DDR3 could help!