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How much current does the VBAT pin draw on the sbRIO-9606?

I would like to provide a vbat voltage to the sbRIO-9606 in order to keep the RTC accurate. I am having a hard time finding information about how much current the VBAT pin will draw to keep the RTC alive. Any recommendations for providing this voltage are welcome.

 

Thanks,

Kristen

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Hello KristenS,

 

The sbRIO-9606 ships with an onboard battery which it can use to power the RMC VBAT. If you look at the sbRIO board, you will notice a relatively large battery with a name and model number printed on it. Search for this battery in any search engine and you should find the product page for the battery containing a datasheet. You can use the battery specification as a starting point. I believe the battery used on the 9606 is a RAYOVAC BR1225 but I would recommend confirming with your hardware.

 

Keep in mind that the user manual for the 9606 on page 25 details the voltage requirements for the RMC VBAT. I have included a link to the user manual for your convenience.

 

OEM OPERATING INSTRUCTIONS AND SPECIFICATIONS NI sbRIO-9605/9606 and NI sbRIO-9623/9626/9633/9636:
http://www.ni.com/pdf/manuals/373378d.pdf#page=25


Regards,


J_bou

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Hi J_bou,

 

Thanks for helping with this question. I am still a bit confused though. Where is there documentation/information about the sbRIO-9606 shipping with a battery? Is this something that comes in the developer kit, but not integrated on the board itself? I have seen forum posts that suggest other RIO boards have a coin cell integrated that is rated for the life of the board without needing a charger, but I don't see anything about this for the 9606 version. If the board ships with an installed/integrated battery, the user would not need to provide an external voltage. Are there any application notes about this that could help?

 

The user's guide does clearly state the voltage requirements if a user wants to provide an external battery to keep the RTC alive, but there is no information about the current draw to tell how fast the RIO will discharge the battery. Does the battery model you mention shipping with the RIO need a charger, or is it meant to last for the lifetime of the sbRIO board?

 

Best,

Kristen

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Hello KristenS,

 

There is indeed no onboard battery for the on the sbRIO-9606 (other sbRIOs like the 9636 do have one onboard battery) so powering it externally will be necessary if you don’t want the onboard real-time clock to reset during a power cycle.

 

My assumption is that the current draw is so minimal that the developers did not include this specification in the user manual. The battery I mentioned above is non-rechargeable and is designed to last a VERY long time in the RIO. If you were to use a small battery similar to the one mentioned above, you should be fine for years.

 

Regards,

 

J_bou

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Perfect, thank you!

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To follow up with a concrete current draw number, it is 600 nA, nominally, with a maximum of 1000 nA.

Tannerite
National Instruments
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