| ??? 01/01/06 17:05 Read: times Msg Score: +1 +1 Good Answer/Helpful |
#106348 - If I understand you correctly Responding to: ???'s previous message |
Mahmood said:
Some people use the VCC line to send some data, is there any chance this would disturb the digital circuitry? Difficult to answer. A Vcc line should ideally be a zero Ohm source. This is provided by the ideal zero Ohm source impedance of regulator and the decoupling measures at voltage regulator and chips. If you want to transmit RF along this Vcc line, then you must increase the Vcc line impedance for the RF again, for instance by inserting a choke between regulator output and Vcc line, and by using RC-, LC- or LRC-filters at the chips powered by the Vcc line. Also, routing the Vcc line over a solid ground plane following the design rules of transmission line technique will prevent the RF from leaving the board. Means, it will prevent the Vcc line from acting like an antenna! This should eliminate all trouble for the digital circuitry. 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 |