ST25R95 - Power Supply issues

[Andreas_HB]

Hello All,

According to the data sheet, there are no specific requirements for the power supply besides the power and voltage requirements. However, if you look at the schematic of the CR95HF RF transceiver Demo board, the design seems to be more advanced. Due to this I have a couple of questions regarding the power supply for the ST25R95.

1. The demo board is mounted with a lot of decoupling. Is this necessary for the reader to work, or is this just to remove noise from the USB supply?
2. Is it necessary to separate VPS_MAIN and VPS_TX?

Best regards,

Andreas

[Brian TIDAL · Accepted solution]

Hi,

this decoupling is the usual way to clean the power supply. This depends on the Power supply distribution and accuracy (some capacitors can be removed if the power supply is clean).

regarding the second point, separating VPS_MAIN and VPS_TX will prevent internal noise propagation from Digital to analog.

Rgds

BT