Other Parts Discussed in Thread: THS4521
Hi
Can someone help to explain where I get wrong with this schematics? I use a differential op-amp THS4521 and want to measure the differential signal coming from a pressure sensor (transducer).
The sensor is powered from 5V and it has a range of 0-1000bar. Without connecting the op-amp at 0 bar it gives differential voltage (between P+ and P-) of 0.14mV and 1000bar it is 14mV.
Therefore I used this op-amp to amplify the voltage and measure it with an ADC.
The ADC has no internal gain, therefore it must be like this.
Problem is that when the sensor is connected to the op-amp it gets an offset of ca 3mV.
After reaching 25bar the values on the output of op-amp go below 0mV. Since I cannot measure negative differential voltage with the ADC, I have a problem.
I could swap P+ and P- but then I cannot read anything below 25bar.
Sensor is powered from 5V source, the op-amp from 3.3V. Rest is on the attached picture.
Does anyone has experience with this op-amp and could tell me some hints?