About using the ST25DV-Discovery

[wxuan.1]

Hello.

I use the ST25DV-Discovery to test the lower power mode of the ST25DV04K.But I run the demo downloaded from the ST.When I use the low power mode,the current consumption is up to 145uA.In the document of ST,the current consumption is only blow 1uA. How can I do to reduce the current consumption?

[JL. Lebon]

Hello,

Can you please tell us where you are measuring the current ?

If you look at the schematics of the antenna board, you can see that the ST25DV04K is powered by a VCC signal. This VCC signal is also powering some pull-up resistors, so if you measure the current on VCC, you are measuring the consumption of the ST25DV and the resistors.

Best regards.

[wxuan.1]

Thank for your response. Actually, I measure the current on the VCC.So,this measure is wrong?If it is wrong,how can I get the real current consumption about the ST25DV device.I need to design a low power product,how can I reduce the current consumption in the circuit of ST25DV04K? I need the current consumption low to 1uA.Can it be done?

[wxuan.1]

Another question,is the Icc1 current consumption contain the whole circuit? If not ,which part is the Icc1 measure?

[JL. Lebon · Accepted solution]

Hello,

Yes, the Icc1 is the current measured on VCC pin, so it is for the whole circuit.

Power consumption down to 1uA can be done by setting the LPD pin to high level.

Please be aware that the LPD pin is available only on the 12-pin package of the ST25DV04K.

About your measurement:

As described in the datasheet, there is different packages available for the ST25DV04K. Some packages have 8-pins, others have 12-pins. As shown in the datasheet, only the 12-pins version have the LPD pin that allows to enter in low power mode.

If you have a ST25DV-Discovery kit for the ST25DV04K, then you have the SO8 package (8-pin package). In this case you don't have the LPD pin, and you can't activate the low power mode.

If you plan to use the ST25DVxxK version, you need to get the 12-pin package. This is available with the X-NUCLEO-NFC04A1 development board (https://www.st.com/en/ecosystems/x-nucleo-nfc04a1.html).

Or you can order the ST25DV64KC-Discovery kit for the ST25DV64KC (newer version of the ST25DVxxK) , which is delivered in the 12-pin DFN12 package and then you can use this one to test the 1uA Low power mode.

If you need to design a low power application with the ST25DV, there is this application note that can help you optimize the power consumption: https://www.st.com/resource/en/application_note/an5733-using-st25dvi2c-series-for-ultralow-power-applications-stmicroelectronics.pdf

Best regards.