Timeline for How do PCB vias affect signal quality?
Current License: CC BY-SA 4.0
4 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Apr 12, 2019 at 16:08 | comment | added | Voltage Spike♦ | Grounding for scopes can be a big problem, if you go faster than 30MHz+ the grounding wire inductance of the probe starts to become noticeable and you need to take steps to make it as short as possible. | |
| Apr 12, 2019 at 15:57 | comment | added | Jeff Wahaus | The SPI bus is going through a TXB0108 level shifter (5 to 3.3V) so I was expecting the 3.3V signals to be pretty clean. The noise I was seeing was apparently due to how I had the scope connected to the bus. The SPI bus has 3 devices on it, two within 2 cm of the level translator and one about 5cm distance. The furthest device is socketed so I removed it to use the socket pins to attach the scope. With the 3rd device removed the signals had significant noise. I re-measured with the 3rd device attached and the noise was significantly less. | |
| Apr 12, 2019 at 15:42 | vote | accept | Jeff Wahaus | ||
| Apr 11, 2019 at 16:38 | history | answered | Voltage Spike♦ | CC BY-SA 4.0 |