How to disable the RF section in M24LR64E-R. I am using only I2C interface for my application and I want to avoid any unnecessary radiation from the chip

[JL. Lebon]

Hello,

Unfortunately, it is not possible to disable the RF interface in M24LR64E-R.

Nevertheless, in the ISO15693 RF technology (on which the M24LR64E-R is based) the tags are completely passive. Only the readers are emitting RF magnetic field. The M24LR64E-R, as a tag, is never emitting any RF signal at all.

The principle of this technology is that the RF reader is emitting a 13.56MHz signal to the tag, modulating it to transmit data. To answer, the tag is in return also modulating this very same signal emitted by the reader. The reader is always talking first, the tag can't initiate the communication.

The tag (M24LR64E-R) is never emitting any signal by itself.

So you don't have to fear any radiation from the M24LR64E-R.

If you want a dynamic tag on which you can disable the RF interface, you can have a look at the ST25DV64K, which has similar functionalities as the M24LR64E-R, plus others , among which the possibility to disable the RF interface completely (RF sleep mode).

Hope this answers your questions.

[SRoy]

@JL. Lebon_O​ Thank you very much for the reply. So what I can conclude from your answer is that there is no danger of unwanted emissions when I go for my RE test.

Also, I would like to know is there any chance of malfunctioning of the device when it is subjected to electromagnetic fields like we have in the Radiated susceptibility test. I mean the the RF antenna shall not pick any unwanted signal. The whole idea is that when I go for EMI/EMC test, there should not be any failure. We do not want to go for some other part as we already have the drivers for this part and we are running tight on our schedule.Looking forward for your reply.

[JL. Lebon]

​Hello,

In first message, you said that you are only using the I2C interface in your application. Do you have any antenna on your PCB, or anywhere on the application, connected to AC0/AC1 pins of the M24LR ? How are those 2 pins connected ?

Best regards.

[SRoy]

JL. Lebon :

Hello,

On my PCB, there is no Antenna. I have kept the AC0/AC1 pin NC(Not Connected). Is this fine?

Also, let me know if I keep RFbusy and Vout Pins NC as well since I am going to use only the I2C interface.

Please suggest.

[S.Ma]

Why not checkout for a pin to pin compatible EEPROM without the antenna? Might be cheaper too.

[SRoy]

@

KIC8462852 EPIC204278916 This is the EEPROM present on the STM32F779 Eval kit.Due to shortage of time ,I donot want to go for another EEPROM as I already have the driver for this.

Hence,I only want to make sure that if I go with M24LR, I should not face any EMC issues.I hope you understand my problem.

[JL. Lebon · Accepted solution]

​Hello,

Sorry for my late reply to your last question.

Yes, it is safe to keep AC0/AC1 not connected. This is not something that we usually do, but I foresee no problem with EMC.

You can also keep RFBusy and Vout unconnected. This is safe as those are output only signals.

Best regards.