DRV2605L: Open-loop mode issue

Hello,

We are using the DRV2605L in our product, we decided to switch to an LRA requiring open-loop operation. We are only using RTP mode.

I am however having trouble to make it work properly. I switch to demo boards to make it easier to debug (2305 Adafruit) and I get some very surprising results:

• When using one of the demo board (Adafruit 2305), everything works as intended, I can drive the LRA in open-loop.
• when using a second demo board (still Adafruit 2305 but different physical board), with the same software, then the DRV2605L only runs in close-loop.

Any idea what could be the issue here?

Thank you in advance,

Rémi