PN5190 tuning

[jr_hernandez]

Hello,

I have a couple of questions related to NFC tuning tool.

1. I have chosen PN5190 as reader in the first 4 comboBoxes, but then in the matching network part  there is a checkBox for several readers and not sure If I should check it or not. I think PN5180 is very simialr to PN5190. Can you please confirm If I have to check it fo rmy PN5190.

I have set L0 as 160 nH (as in the kit PNEV5190) and it says this value is too low

2. There is a warning whe calculating matching nettwork: "The inductance of L0 might be to low: this can cause the DPC correlation to fail."

I am planing not to use internal DC-DC regulator, so DPC is not possible, right? Then, I think I could still use 160 nH as L0, right?

3. When I calcualted the values some month ago there was no such warning. Have you updated the tool?

Regards, Ramon.

[jr_hernandez]

Hi Renke,

Thanks for the info.

Eventually, I have connected my board to the kit so I can use NfcCockpit and figure out the root cause.

It comes up my board inlcudes an outdated FW for  PN5150 (FW 2.1):

After upgrading to 2.F5 there is an alert I do not quite understand:

When setting RF on just a very light  burst comes out from the antenna.

14443A protocol loaded and there is an error when doing single-REQ:

I guess there are some missed or corrupted RF values set in EEPROM.

Is there anyway to come back to EEPROM defaults?

Regards, Ramon.

[jr_hernandez]

Hi, Renke,

Thanks for your comments.

OK, I see the DPC is handled by the TXLDO.

I am working on the tuning of my custom board and I have a question regarding the VDDPA.

I have monitored VDDPA  with scope and curretnly I have 0,6V, which is very low., right?

I have forced the value to be 3V9 and still 0,6V appears in the VDDPA pin.

Is this related to detuning on my antenna or sth else?

How important is the initial calibration?

Regards, Ramon.

[renkebienert]

Hi Ramon,

fair and good point: many thanks!

We will update the tool to provide the correct input for PN5190, too.

Anyhow: 

@ 1) Please ignore the warning as of now. Such a warning is valid for the PN5180, but not for the PN5190.

@ 2) The use of DC-DC is independent from the use of the DPC. So DPC can be used, even if the DC-DC is not being used. However, please consider the power level and heat sink: the DC-DC automatically reduces the VUP, if VDDPA goes down. That helps to keep the TxLDO losses as low as poosible. Without the DC-DC the TxLDO losses can increase and might then cause heating problems!

@ 3) That is strange indeed, and we will check. Many thanks for the feedback!

BR, Renke

[jr_hernandez]

Hi again Renke,

AS far as I know my tuing is close to the expected values (17 Ohm): 18-3j 

But no RF is properly generated. When using LPCD the VDDPA seems too low, but still the reader detects the card on field, but no way the UID is read.

[jr_hernandez]

In the very begining I had a big capacitor missing in the EMI filter and had this impedance (31 ohm @ 13,56 MHz):

Curiously, the redaer was able to read UID and memory of ISO15693 card @ 60mm.

Is it possible that impedance is too low whie my new tuning, and current too high so VDDPA is turned off somehow?

Regards, Ramon.

[renkebienert]

Hi Ramon,

yes, that might be, but

17 Ohm normally is high enough to not exceed the default target current, so DPC shall not reduce VDDPA

even if the VDDPA is reduced by the DPC, the lowest values shall be 1.5V.

So I guess, either the chip is damaged or the RFon does not work due to a missing load protocol?

BR,

Renke

[jr_hernandez]

Hi Renke,

Any update with regards to my problem with NfcCockpit described above?

Regards, Ramon.