Hi I have just been given a project at work and we are magnetically stress testing DUTs at extreme temperatures going from -40 Degrees Celsius to 200 Degrees Celsius, I need to come up with a way that we can read the magnetic field strength while we are testing. I have tried looking into a hall sensor but i would need it in die form and cant find it anywhere especially in the temperature range given. Do ye have any suggestions, I only started as a Co-Op student and am drawing blanks as don't have much experience in this field.

  • \$\begingroup\$ Does the magnetic field sensor need to be in direct contact with the DUT? If not, you could insulate it along with a heater to keep its temperature closer to 200C \$\endgroup\$ – τεκ Jan 21 '19 at 16:06
  • \$\begingroup\$ the sensor wont be touching the chip but we do have to incorporate it into a package that we have made that sits on top of the chip which has the magnet integrated. as a result of this we need the sensor in bare form and i am not getting any responses from the manufacturers that i have contacted. \$\endgroup\$ – MeghanF Jan 21 '19 at 16:53
  • \$\begingroup\$ Do you really need it in die form or are you talking about a chipscale (BGA) type package? If it's the former how are you going to bond out the connections? There are some smallish SON type packages available too, what are your dimensional requirements? I don't know of any Hall effect sensors rated higher than 150C, so that may be an issue for lifetime and accuracy. \$\endgroup\$ – John D Jan 21 '19 at 17:23
  • \$\begingroup\$ My boss said it does, as if i had to build it onto a pcb there are only a few pcbs that will be able to take that temperature range and the bulkiness wont be able to fit into our package. I have to come up with a plan b option if i cant find a bare die, however i might have just found one but it is rated up to 150C, would you know if it is possible to insulate a bare die so it might be able to reach the 200C \$\endgroup\$ – MeghanF Jan 22 '19 at 9:39
  • \$\begingroup\$ @MeghanF You're unlikely to be able to insulate the die if you're so space-constrained that you need bare die in the first place. You might be able to characterize the part at 200C to see what kind of performance and lifetime you can expect, but there are no guarantees, and the manufacturer likely won't be of much help unless you plan to buy millions of them. \$\endgroup\$ – John D Jan 22 '19 at 18:42

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