Hello,
From datasheet of DRV425, the max sensor range is +/-2mT, the saturation magnetic field is above +/-3.6mT.
Is that possible it is used to measure magnetic field bigger than 2mT, such as 2.4mT?
Below is the calculation, it seems ok based "system parameter calculator."
But why "max field: 2mT" is noted? What problems would be met if it's used to measure magnetic field bigger than 2mT?
Hello User,
The DRV425 cannot measure much over 2mT but you need to make sure it can be measured for your conditions based on the calculator. There is a tab in the calculator that you can see the range for your conditions.
Any time the field is above approximately 3.6mT the sensor is saturated and the ERROR goes active low to advice you the sensor is out of range. This is for the example of 2mT being the maximum field that can be compensated in the datasheet. This value is 1.6mT above the maximum compensated field.
So for example if you are only going to 85°C and you have a Rshunt of 10Ω and will be using 5V and a Reference of 2.5V your maximum compensation field at room is 3.58mT at room temperature and 2.54mT over temperature.
For the Error-Flag will go active at room 1.6mT above 3.58mT = 5.18mT, but the maximum sensing range is 3.58mT at room temperature.
Over the temperature range the Error-Flag will go active at 1.6mT above 2.54mT = 4.14mT, but the maximum sensing range is 2.54 over temperature. I have included a picture of the calculator.
Hello Javier,
It's clearer for me now.
Below calculation is based on the extreme conditions/worst case at my side.
I still have 3 questions:
1. The "maximum compensatable field" is limited by railing of the compensation coil driver, right?
2. The " saturation error flag trigger level (DC field)" is 5.12mT and 4.15mT seperately. But not (3.1mT + 1.6mT) and (2.22mT + 1.6mT), as you metioned in last mail?
Does the "saturation error flag trigger level (DC field)" means the Error-Flag in your last mail - "For the Error-Flag will go active at room 1.6mT above 3.58mT = 5.18mT, but the maximum sensing range is 3.58mT at room temperature."
3. When " Over-Range Flag will never trigger" is "Error" or " Warning", the OR will not be active. But why?
Hello Javier,
It's clear for questions 1 and 3.
But for question 2, still in your example, what i ask is: "Saturation Error Flag trigger level" = "Maximum Compensatable Field" +1.6mT?
Hello Javier,
Yes, I understand the "Maximum Compensatable Field" and the reason of vary with temperature, based on below temperature.
But, for "Saturation Error Flag trigger level", my questions are:
1) as you metioned - " Any time the field is above approximately 3.6mT the sensor is saturated".
so, can I say, in your example, the Error Flag does not work when 3.6mT is applied?
2) the Error Flag works when 5.43mT at room temperature in your example?
still, 5.34mT ≠ 3.58mT + 1.6mT, whichi is "Saturation Error Flag trigger level" ≠ "Maximum Compensatable Field" +1.6mT?
