Question
According to article marked AN-688, ADXRS150 has a first-order system which is
dominated by its output filter. our engineers think, in other words, step input
should has non-overshoot if the system is a first-order system.
During our test, after giving a step input signal on ADXRS150, second-order
system which has a obvious non-overshoot features its output.
Now that there is difference between us, we want to get your confirmation.
Is ADXRS150 has first-order system or not? And how can we get the right testing
result if we were wrong?
Answer
The ADXRS150 is, strictly speaking, a second order system. However in most
applications, where the low pass filter pole formed at Cmid is more than 10
times higher in frequency than the output filter, it acts like a first order
system. If you are concerned about getting step response that looks more like
first order, simply make the Cmid capacitor smaller.
That said, you would be much better off using our latest generation of gyros
(ADXRS61x). The have much better performance. They are truly first order
systems (there is no Cmid capacitor). You can see one at
http://www.analog.com/en/prod/0%2C2877%2CADXRS612%2C00.html