aaron_do wrote on Apr 19th, 2012, 8:10am:I agree...your method sounds wrong. What kind of signal are you trying to measure?
Aaron
Btw, oscilloscopes use 10:1 probes to solve that issue...but maybe there is a better method in your case.
Sorry to reply so late.
My signal is a digital signal before the CDR ckt. Its swing may be as large as 1.5*VDD. But since the instrument has an impedence of 50 ohm, the driver must steer a large current, thus the large W/L.
I don't understand the 10:1 probes in my case, could you please explain it more clearly.
Thanks a lot~~~