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Hello,
Hope you are well.
I've been using the LDC1000 for position sensing. Recently, I tested the LDC1101. I just wanted a quick confirmation on something.
On the LDC1000, when my sensor is closest to the target (lowest Rp), I receive the high end of the digital values (approx. 30,000 digital codes) - as I move away, the sensor counts decrease.
On the LDC1101, when my sensor is closest to the target (lowest Rp), I receive the low end if the digital values (0 digital codes), and as I move away, the sensor counts increase.
I had a look at the data sheet as confirmation, but I just wanted to double confirm that this is the case.
Another question I have is that on the data sheet, the LDC is described as working by maintaining the LC tank oscillation to a constant level. Can I just confirm, is this the voltage level across the oscillator that's being maintained? I just did a scope of it and it seems like it's the voltage that's being regulated - the below plot is for the LDC1101.
Best wishes,
Eric
Hello Eric,
With the LDC1101, are you using the device in RP+L mode or LHR mode? The relationship of the L data is different between the two modes. This shows up in the equations to calculate frequency from the datasheet:
RP+L:
LHR:
The constant level mentioned in the datasheet is referring to the amplitude of the signal.
Best Regards,
Justin Beigel
Hello Eric,
The snapshot you shared is fairly noisy but looks correct.
Single ended measurement (Yellow is INA, Blue is INB):
Differential measurement: 
The LDC1101 regulates the waveform to a consistent amplitude and monitors the decay to determine the Rp and the frequency to determine L.
Best Regards,
Justin Beigel
