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sinara-hw / FMC_Shuttler

16-channel 125MS/s 16bit DAC in FMC form factor.
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DAC_AFE-resistances #28

Closed giozara closed 8 months ago

giozara commented 2 years ago

In the DAC_AFE schematics the resistances on the ADA4896 are different from the one in the note. Is that intentional or is there a reason which eludes me?

giozara commented 2 years ago

@gkasprow @kaolpr

gkasprow commented 2 years ago

It's just an opamp. We need resistances that give required gain. I don't see any reason to use the same as in the datasheet

giozara commented 2 years ago

I was just wondering, because the note in the same schematic specifies higher values which would lead to a higher gain than the one currently chosen. Were the previous (higher gain resistance pair) railing it?

gkasprow commented 2 years ago

It's possible there is some error. Did you calculate the entire gain budget from the DAC up to the AFE output? Here are my simulations and calculations SIM_CALC.zip

maciejprzybysz commented 8 months ago

As I see in v1.1 resistors value on schematic, simulation and in the table are the same. I don't see what we could improve here in the next revision, so I'm closing the issue for now. If you have any suggestions feel free to re-open.