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9683 RMC card: current sourcing capabilities of LVTTL 3.3V supply and DIO pins

Hi,

I am attaching another custom made board on top of the 9683 RMC.

There, I need to feed some 3.3-Volt circuitry, which will demand about 24-30 mA.

I am tempted to draw that current from pins 1 and 3 of the 60-pin LVTTL connector... however, if these pins behave like the other pins, because the manuals say that only a 3-mAmp supply is guaranteed per pin, I would get just 6 mA.

So, how could I manage to get from 24 to 30 mA? Does it make sense to configure other DIO pins as outputs, and set them high, e.g. all eight DIO7:0 simultaneously, to source 24 mA?

Thank you!

Biscay.

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Re: 9683 RMC card: current sourcing capabilities of LVTTL 3.3V supply and DIO pins

Pins 1 and 3 of the 60-pin LVTTL connector are not limited by the 3 mA spec of the signal pins. These +3.3V pins are connected to the FPGA_VIO rail on the sbRIO, which can supply up to .33 A.

 

Will

National Instruments

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Re: 9683 RMC card: current sourcing capabilities of LVTTL 3.3V supply and DIO pins

Will,

Thank you for your reply!

However, out of those 330mA that the FPGA_VIO rail can supply, how many are consumed on the RMC, and, then, how many are left for "other uses" such as mine?

Biscay.

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Accepted by topic author biscay
02-01-2018 02:27 PM

Re: 9683 RMC card: current sourcing capabilities of LVTTL 3.3V supply and DIO pins

The RMC itself will consume approximately ~71mA typical or ~228mA max from that rail. So you should be fine pulling an additional 30 mA.

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Re: 9683 RMC card: current sourcing capabilities of LVTTL 3.3V supply and DIO pins

Great! Thanks again. Biscay.

PS: I may have missed all that information in the manuals, but in case I didn't... I think it's a good idea to provide these figures in the datasheets etc.

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