Hi,
I am currently designing a sensing system using DRV5055A4QDBZR.
I need to use the analog signal output of the IC to determine the position of an axially magnetized NdFeB magnet.
I would like to know if DRV5055A4QDBZR has a large sensor variability across sensors and batches for the same applied magnetic field. If so, how large is the sensor variability?
This is to know if calibration will be required to precisely place the magnets in the same position across different circuits.
Thanks.
Zac,
Welcome to E2E. Thanks for reaching out with your question.
The sensitivity variation for DRV5055A4 is shown in the table entry below
When operating at 3.3V this varies from 7.1mV/mT to 7.9mV/mT. So considering an applied input of 100 mT, then there could be as much as 80 mV difference on the output.
Part of what this means to your end system really depends on the typical operating conditions you expect. The strength of the magnetic field will varies with a 1/r2 relationship, so when close to the magnet the strength is high, but there will be a non-linear and exponential decrease as the range increases. At close range, the die to die variation might not necessarily equate to as much error in position as it will at longer range where larger changes in position only yield a small change in the output voltage.
A simulation tool which you might find useful is here:
https://webench.ti.com/timss/
The tool models the typical case for the linear sensors, but you can capture the expected magnetic fields, download a csv report, and then do a little bit of post-processing to check for the total impact on your calculations.
Thanks,
Scott
