Other Parts Discussed in Thread: LDC1001
Tool/software:
I've been trying to adjust a filter cap on an existing sensor (CFA and CFB pins). The datasheet says to adjust the cap until the signal on the CFB pin is 1 Vp-p. The board has air coil, and the existing filter cap is 15pF. The problem is that I see no signal on the CFB pin. When I probe with respect to GND, I only see noise. When I probe with a differential probe from CFA to CFB, I can see a tiny signal that is the same frequency as on the coil, but only tens of millivolts in amplitude. I dropped the filter cap value to 5pF, but the signal didn't get any larger. Should I reference my measurement to GND or CFA? What frequency should the signal on CFB be? Should it be the same frequency that is on the coil?