Exposed pad in Stm32wb55rg connection with gnd mandatory or not?

[ajaykrishna097]

In my design I left the exposed pad in Stm32wb55rg VFQFN68 package. when I try to flash the device using st link , iam getting error "target not found". I am check the design and found i left the epad (69th pin) floating. Does this cause any issue ?. Please help me out here .thanks @Amel NASRI .

[STTwo-32]

Hello @ajaykrishna097 and welcome to the ST Community :smiling_face_with_smiling_eyes:.

So, as indicated on the DS11929, the exposed pad must be connected to ground plane:

 So, for a working design, you need to connect the exposed pad to the GND plane.

Best Regards.

STTwo-32

[ajaykrishna097]

Just to reconfirm, if I didn't connect the exposed pad to gnd then my design "will not work". Sorry for asking it again , if this is a issue that will for cause the MCU to not work, then I will redesign and initiate the manufacturing.

[STTwo-32]

To guarantee that the PCB will work on the best conditions, you should connect the exposed pad to the GND plane.

Best Regards.

STTwo-32