Other Parts Discussed in Thread: MIO
Hi,
I designed a board for your PGA970 to drive a 4-wire LVDT with +-5mm full-scale.
With PGA970 I proved I can measure distances with a rms noise of 0.3um superposed on the amplitude measurement (translated into distance) and about 1° rms superposed on the phase measurement, which is enough for my application.
Nevertheless, when the magnetic core is near to the central position the measurement of the phase becomes extremely noisy, with a rms noise of 60° (so, in the center I see 90°+-60°). In this condition, it is extremely difficult to determine if the core is left or right when the LVDT is operated near to the center, so the sign of the measurement result is not stable. In my case a rms noise of 60° translates into about 5um noise in the central part (in a range of about 5um around the center), which cannot be accepted for my application.
Is this one a known problem? Do you have any suggestion to solve it?
Thank you for your time.
Best regards,
Alessandro Cominelli