| ??? 12/30/05 17:51 Read: times |
#106242 - Depends Responding to: ???'s previous message |
Erik said:
ordinary, garden-variety, low-Q capacitors will work better in your digital application This is not of general validity! It may be useful with multilayer boards, where for Vcc and ground own layers are used. Then, the inter-layer capacitance can form resonances in combination with the additional decoupling caps. In mixed applications, on the other hand, where analog and digital circuitry is used on the same board and where extensive filtering of the individual supply voltages is needed to prevent the noisy digital currents from running over the common ground star point, the use of low-ESR caps is essential, especially for the digital circuits! You can see the effectivness of caps: Just measure the ripple and you will see what's needed... In this case I do not use Vcc planes, but only a solid ground plane. This one is splitted into the analog and digital section. Where very high precision is needed I use a pi-filter in the supply line of each analog and digital chip. Kai |
| Topic | Author | Date |
| capacitors: better is not better | 01/01/70 00:00 | |
| Which all goes to show... | 01/01/70 00:00 | |
| Depends | 01/01/70 00:00 | |
| Analog Supply | 01/01/70 00:00 | |
| More details? | 01/01/70 00:00 | |
| question in another way | 01/01/70 00:00 | |
| If I understand you correctly | 01/01/70 00:00 | |
signals over Vcc | 01/01/70 00:00 | |
| Yes, low-Q means high-ESR | 01/01/70 00:00 | |
| 'Low-Q' = 'high-ESR' | 01/01/70 00:00 |