TRF7961: Extend the distance to 40cm

Danilo A.

Part Number: TRF7961
Other Parts Discussed in Thread: TRF7970A

Hi Team,

Our customer used the TRF7961 for their product development. Using the application schematic in the datasheet, they were able to get about 12cm reading and writing distance. Is there any solution to extend the distance to 40cm?

Regards,

Danilo

over 4 years ago

0 Helfried Vollbrecht over 4 years ago

TI__Mastermind 18265 points

Hello Danilo,

to achieve an operating distance of 40cm it would require a high power reader. The TRF79xxA devices are not able to achieve this distance.

The operating distance will also depend on the tag type used. With ISO15693 compatible tags a larger distance can be seen as with ISO14443 tags. With a large antenna and an ISO15693 tag with a credit card size antenna, even when the system is well tuned, no more then 25cm can be expected.

Best Regards,

Helfried

0 Danilo A. over 4 years ago in reply to Helfried Vollbrecht

TI__Mastermind 30980 points

Hi Helfried,

Thank you for your response.

In the customer's application, they use a credit card size 15693 tag. They implemented the schematic diagram shown in SLOU186G –AUGUST 2006–REVISED MAY 2017. With this schematic diagram and 5V DC supply and a credit size antenna as shown in TRF796x EVM, they were able to achieve 12cm only.

The customer would like to know what size of antenna can achieve close to 25cm distance. He would like to see the parameter of the large antenna you have mentioned and would like to know if it is possible to insert an amplifier to get a longer distance.

Lastly, he would like to know if there are updates with regards to HF Power Amplifier (Reference Design Guide) which is issued in 2008. Please refer to the file in the link below.

https://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/667/3348.appnote_5F00_trf796x_5F00_pwramp_5F00_4w.pdf

Regards,

Danilo

0 Helfried Vollbrecht over 4 years ago in reply to Danilo A.

TI__Mastermind 18265 points

Hello Danilo,

sorry for the late answer.

I have check about the size of the antenna and found information in the TRF7970A FAQ. Please see chapter 1.4.

https://www.ti.com/lit/pdf/sloa248

TI can not support any power amplifier designs for NFC. This is also mentioned in chapter 5.1. The application note you referred to, did not get any update and had no further progress. TI has focused only on applications with short reading distances.

Best Regards,

Helfried

0 Danilo A. over 4 years ago in reply to Helfried Vollbrecht

TI__Mastermind 30980 points

Hi Helfried,

Thank you very much for these information.

Regards,

Danilo

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TRF7961: Extend the distance to 40cm