Microstrips are cool

29.11.2005 19:35

The PCB Trace Impedance Calculator is incredibly useful, even if you aren't into microwave circuits and transmission lines.

For example: I was worried that the guard ring and ground plate I made around the lines leading from quartz crystal to the CPU on my keylogger PCB will significantly affect the capacitance from these lines to the ground. So I've entered the correct geometry into the calculator and it returned that the parasitic capacitance to ground is around 2pF/inch. Since these lines are around an inch long the parasitic capacitance is well within the tolerance limits (Atmel says that the capacitance to ground must be 30pF± 10pF) and I can be sure the oscillator will work fine.

Posted by Tomaž | Categories: Analog

Add a new comment

(No HTML tags allowed. Separate paragraphs with a blank line.)