Hi,
I am planning to use AD5522 FIMV (2mA range).
In this current range what is the correct connection of EXTFOHx, EXTMEASIHx, EXTMEASILx pins.
Should I leaved open or all connected to FOHx pins?
Thanks
Oki
AD5522
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The AD5522 is a high performance, highly integrated parametric measurement unit consisting of four independent channels. Each per-pin parametric measurement...
Datasheet
AD5522 on Analog.com
Hi,
I am planning to use AD5522 FIMV (2mA range).
In this current range what is the correct connection of EXTFOHx, EXTMEASIHx, EXTMEASILx pins.
Should I leaved open or all connected to FOHx pins?
Thanks
Oki
Hi, oki.developer.
Thanks for your interest in AD5522. You can follow this functional diagram from the datasheet:
As you can see, FOHx isn't left open and is connected to the DUT. You'll need FOHx connected because this line is used for the internal current ranges (including the 2mA range you are trying to use). Be use to set 2mA using AD5522's internal registers.
Thanks,
Mac
Hi Mac,
Thanks for the fast response.
Maybe i didn't clarify my question. I know i shouldn't leave open FOHx and MEASVHx and CFFx pins. They have to connect each other (CFFx with 220p capacitor). My question is about EXTFOHx and EXTMEASIx pins. I think they are related only if you use external Rsense resistor. Am i correct?
Please check attched circuit.
Hi, oki.developer.
Thanks for the clarification. If you don't wish to use the external current range, you can do that. But I personally think that if you're going to design your board, even if you think you won't use the external range, it is still better to keep it connected to the DUT. The same goes with the EXTMEASIHx and EXTMEASILx. It is better to connect them to an rsense. Just making the external range handy if you ever want to use it at some point. You can always disable the external range via AD5522's registers anyway.
Thanks,
Mac
What do you mean by keep it connected if I am not using external range?
You mean EXTFOHx and EXTMEASIHx tied together FOHx pin.?
Or just in case use 100R external resistor like eval board?
You always have to use a sense resistor if you are not going to leave EXTFOHx, EXTMEASIHx and EXTMEASILx open.
Got it. Last question. If not use external register can i leaved those pins open. Is it makes 2mA range unstable?
The internal ranges not being stable is unexpected when EXTFOHx is left open as the feedforward capacitors are independent of the external current range.
Thanks a lot. It's really helpful. Good day.
Hi Mac,
I have another question about PMU register.
For FIMV mode what is correct register values?
I think x0F29B300 looks correct to me. What you think?
Also I am confused MEAS1|MEAS0.
So, Forcing I Measuring V mode MEASOUTx should connect Vsense?
Is that right?
Hi, oki.developer.
Yes, you got the right HEX code. And yes, Measure V mode connects Vsesnse to MEASOUTx.