AD698 LVDT Signal Conditioner

Hi Dan,

      The AD698 is a single chip solution Signal conditioner for Linear variable differential transformer. The AD698 is placed between the sensor and ADC. It converts transducer mechanical position to a unipolar or bipolar scaled dc voltage with high degree of accuracy and repeatability. The DC voltage will then be feed to an ADC to be converted into digital form.

Regards,

Jonathan

Yes, I understand that.

I was asking about the accuracy of the device.

I don't think it is better than 12-bits accurate.

I was looking for confirmation.

Thanks,

Dan

Hi Dan,

          The ability of the signal conditioner to perceive changes on the sensor output signal will limit the resolution of the system. To reduce noise in the system, you can do oversampling and get an average output result from the AD698 but this comes with expense in system bandwidth. The accuracy will be affected by accuracy, gain and drift spec. The AD698 linearity spec typically at 75ppm will have an 13.7 bit accuracy, the worst would be at 500ppm which is a 11 bit accuracy.

Regards,

Jonathan

Hi,

As per last response, The AD698 linearity spec typically at 75ppm will have an 13.7 bit accuracy, the worst would be at 500ppm which is a 11 bit accuracy.

So, instead of using AD7992 which is12 bit ADC, if i use 14-bit or 16-bit ADC, what would be possible good / bad out comes?

say, I'm connecting AD698 to AD8615 and then to AD7992 as reference circuit.

case 1) my o/p at AD815 is uni-polar 0 to 5V.

                 5V / 4096 for 12 bit ADC= 1.22mV/Step.

case 2) my o/p at AD815 is uni-polar 0 to 10V.

                 10V/4096 for 12bit ADC = 2.44mV/Step.