ST25DVxxx V_EH pin characteristics

[Mike xx]

Posted on June 22, 2018 at 01:40

I'm wary about assuming anything that doesn't have a firm specification and the V_EH pin seems to have very little information about it.

1) The datasheet says 'When the Energy harvesting mode is disabled or the RF field strength is not sufficient, the energy harvesting analog voltage output V_EH is in High-Z state.' What is the specification associated with this High-Z state? Specifically what is the reverse leakage?

2) I cannot see any specification associated with V_EH output voltage vs current characterisitcs. Do they exist? I apreciate it will be a function of the RF field. What is the unloaded voltage on the pin?

Is this the best IC for the job?

Any assistance would be greatly appreciated.

[Mike xx]

Posted on June 29, 2018 at 11:16

Is there another device that has a better specified V_EH performance?

The lackof reply doesn't instill me with much confidence for this device.

[JL. Lebon]

Posted on June 29, 2018 at 15:45

Dear Mike xx,

You can find figures of V_EH output voltage versus current in function of RF field strength in a dedicated application note 'AN4913', available on st.com website at the following address:

https://www.st.com/content/ccc/resource/technical/document/application_note/group0/c2/1f/83/75/2c/f1/41/78/DM00329035/files/DM00329035.pdf/jcr:content/translations/en.DM00329035.pdf

 

Regarding the impedance value of V_EH pin in High-Z mode (and associated possible current leakage), I will check and come back to you as soon as possible.

Best regards.

[JL. Lebon · Accepted solution]

Dear Mike xx,

Sorry for the long delay of the answer. As you have noticed, ST community web site has been moving and this introduced some delays in answers.

Some measurements of the input leakage current on V_EH pin has been on a production lot.

• At ambient temperature (30C), the input leakage on the V_EH pin is 500nA when V_EH is High_Z and a 5.5V voltage is applied on the pin.
• At 90C, the input leakage on the V_EH pin is 5uA when V_EH is High_Z and a 5.5V voltage is applied on the pin.

I hope this answer all your questions.

Best regards.