marvin1
Newbie level 5
Hello, I am quite confused about using the fundamental trap to remove fundamental mode oscillation. I use sa612 and in datasheet application circuit the advised values to remove fundamental frequency are 1nF and 0.5 to 1.3 uH. This values remove the frequency of 4.4 to 7.1 MHz.
However the proposed crystal is 44.545 MHz in 3rd overtone. Does not that mean the fundamental frequency must be 44.545 / 3 = about 14.8 MHz, so frequency around 14.8 MHz has to be removed, isn't it? I am using 48.9 MHz, so the fundamental trap should be at around 16.3 MHz. If that's not the case, then how do I calculate the values needed for LC in series?
However the proposed crystal is 44.545 MHz in 3rd overtone. Does not that mean the fundamental frequency must be 44.545 / 3 = about 14.8 MHz, so frequency around 14.8 MHz has to be removed, isn't it? I am using 48.9 MHz, so the fundamental trap should be at around 16.3 MHz. If that's not the case, then how do I calculate the values needed for LC in series?