How to send the MFRC522 RFID module into sleep mode? I'm trying to get the power consumption of a MFRC522 RFID module down, currently while running it consumes about 4mA. There should be a way to put it into sleep mode, I just can't find any documentation on it. I'm using the module with a arduino currently if that helps; and this is the module itself : MFRC522
http://www.nxp.com/documents/data_sheet/MFRC522.pdf

Look at section 8.6.2   Soft power-down mode.