sm130 RFID evaluation shield works only with specific power supplies

Does anyone know why?

My assumption is that it's an interference issue. Is there any way to absorb any possible EMI with magnets or something?

Hi,
What specific supplies?
Does it have to do with.

Tom.... :slight_smile:

RFID circuit needs clean power, from a linear regulator, not a switch-mode supply.
This is because the way RFID signals are detected involves looking for <mV signals
imposed on high voltage 150kHz oscillation of the tank circuit. Switch mode supplies
put out way more than a few mV at the sort of frequencies in question.

In general any analog circuit requires clean linear-regulated power, unless you know
different.