| ??? 01/21/05 20:15 Read: times |
#85532 - ground noise interference |
when i connect a 12v squarewave into a 4049 logic inverter chip via a transistor, i am getting noise coupling on the output of an op-amp in a different part of my circuit? The inverter chip uses a 12v supply, whereas the op-amp uses a 5v supply. However, both are connected to the same ground plane.
If i isolate the ground of the inverter chip, the noise is removed! Therefore i think the noise is being coupled via the common gnd plane. When i build my pcb, will i have to use two seperate grounds? i only have one 12v supply, however i will be using a 12v and a 5v regulator, so how can i isolate the grounds. Also, the output of the op amp is being fed into a comparator, which is connected via a 10k pull up to port 3^2 of the micro, so this needs to be a clean signal. Does anyone have any suggestions why this noise is happening? |
| Topic | Author | Date |
| ground noise interference | 01/01/70 00:00 | |
| re:ground bounce | 01/01/70 00:00 | |
| Decoupling and filtering | 01/01/70 00:00 | |
| optoisolator | 01/01/70 00:00 | |
| Opto's are not a cure-all | 01/01/70 00:00 | |
| Totally Agree.... | 01/01/70 00:00 | |
| Opto's are not a cure-all?! | 01/01/70 00:00 | |
| opto CAN help, but need not | 01/01/70 00:00 | |
| Apriori assumption | 01/01/70 00:00 | |
| Find the root cause | 01/01/70 00:00 | |
| Ground loops | 01/01/70 00:00 | |
| Noise | 01/01/70 00:00 | |
| Re : Ground Noise problem | 01/01/70 00:00 | |
power supply | 01/01/70 00:00 |