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The datasheet for the ICM-42670-P says of the four RESV pins, "No Connect or Connect to GND or Connect to VDDIO" (page 18).A picture of the pin description table from the datasheet

My question is, is there any benefit to connecting these pins to GND (or VDDIO) vs leaving them floating?

For context, the application I have in mind for this IMU is a small quadcopter, and I will be making use of both the gyroscope and the accelerometer.

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  • \$\begingroup\$ Is there any benefit in your application of the extra weight or weight loss? \$\endgroup\$ Commented Mar 20 at 20:28
  • \$\begingroup\$ Less weight is generally better - but not to the point that cutting 4 extra solder blobs is going to provide me with any benefits. \$\endgroup\$ Commented Mar 20 at 20:29
  • \$\begingroup\$ It depends what you consider as benefit. Less weight? Easier routing by using the pins for GND/VDDIO? Mechanichal or thermal performance? \$\endgroup\$ Commented Mar 20 at 20:34
  • \$\begingroup\$ @Ryderr so what do you consider as a benefit. I mean you say less weight is a benefit then you say that losing the weight of four solder blobs is not going to provide a benefit. \$\endgroup\$ Commented Mar 20 at 21:01

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There is the benefit of added mechanical stability if the pin is soldered.

Other than that, there‘s a benefit of better thermal conduction of heat away from the IC, but this seems not to be a consideration for this type of IC.

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  • \$\begingroup\$ Is it the case that NC pins are actually not soldered to the PCB? I had always assumed the would be soldered to the pad (for extra mechanical stability like you mentioned) but the pad would not be connected to any trace. \$\endgroup\$ Commented Mar 20 at 20:25
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    \$\begingroup\$ In this case, as mentioned in the datasheet, you can solder it to GND, which may provide even better mechanical stability than a single pad not connected to anything. \$\endgroup\$ Commented Mar 20 at 20:29
  • \$\begingroup\$ It can also ease routing, if it's easier to route a VDDIO or GND trace through one such pin to get to a pin that needs to be tied to VDDIO or GND. \$\endgroup\$ Commented Mar 21 at 18:47
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You get better thermal conduction to ground. In addition there are aerospace and military applications that anything floating is a risk and should be grounded. Floating pins can develop potentials with stray/strong electromagnetic fields and this could create problems.

It probably doesn't matter if you ground it but it helps you sleep at night.

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