Question
Our customer used ADXL150, ADXL105, ADXL190, ADXL250 and ADXL278 before, and
she found the relation between the output and temperature is monotonic. That
is: if the temperature increase, the output will increase too. Now she used
ADXL78, and she found the relation isn't monotonic. Below is the output of
ADXL78 at -40 degree, 10 degree and 60 degree. Whether the ADXL78 is
non-monotonic with temperature? Whether we have single-axis product which
output is monotonic with the temperature? Thanks!
-40 degree 10 degree 50 degree
Chip1 Output 653mV 738mV 634mV
Chip2 Output 671mV 735mV 680mV
Chip3 Output 635mV 712mV 687mV
Answer
I have discussed the issue of a “monotonic temperature response” with the
designers, and it seems well known that the XL78 family is not monotonic with
temperature. This is consistent with what the customer had reported.
Analog also offers the XL180, XL950 the XL001 for single axis acceleration
sensing. Based on the characterization data for the XL950 and XL180, it would
appear that the behavior of those devices is monotonic. However, please keep
in mind that this behavior is NOT guaranteed by Analog, and there is always the
possibility that a device will not have a monotonic temperature response. We
do not currently have characterization data for the XL001, however if the
customer is curious about this device (it is a new, not yet released,
industrial vibration sensor) then I can report back once we have collected some
data.