topic Re: OM5578 vs OM5577 field strength in NFC

OM5578 vs OM5577 field strength

jan_visser — Wed, 01 Aug 2018 09:08:11 GMT

OM5578 reader field strength vs OM5577.

Hi, I am developing a NFC reader solution. The tags that I am using have a very small antenna and therefore need a strong field to work properly.

I was looking at the two NFC controller SBC kits (OM5577 and OM5578) and was wondering which one would have the strongest antenna field. I would think that would be the OM5578 since it has a higher voltage for the antenna drive circuit. Is my assumption correct?

Re: OM5578 vs OM5577 field strength

IvanRuiz — Thu, 02 Aug 2018 20:27:13 GMT

Hello,

In chapter 4. of PN7120's User manual, it is shown the Voltage measured with EMVCo reference PICC (Proximity Inductive Coupling Card): https://www.nxp.com/docs/en/user-guide/UM10878.pdf

Which is the same as the PN7150's measurements described in chapter 4.2: https://www.nxp.com/docs/en/user-guide/UM10935.pdf

Regards,

Ivan.

Re: OM5578 vs OM5577 field strength

jan_visser — Mon, 06 Aug 2018 14:54:13 GMT

Hello Ivan,

I've bought both an OM5577 and an OM5578 and did some measurements with a sniffer probe attached to an oscilloscope. The voltage induced in my probe by the OM5578 is about 2 times that of the voltage induced by the OM5577. Also, I could read tags over a larger distance with the OM5578 than with the OM5577.

I'm familiar with the tables in the user manual that you mention. I suspect that the RF performance tables for one of these devices is copied from the other because they are exactly the same for both.

Regards,

Jan