I have a problem on the use of REF5025 and it`s application.
One thing I want to be clear is the output noise that looks like triangle wave from the application TI brahs recommanded.
I designed my REF5025 setting like that :
I mimic the application on the page 12 from its spec. with OPA735.
When I check TP13 - AVSS_2.5V, I watch the triangle pulse on -2.5V baseline like that:
I don`t understand this situation, and I can`t use the output as reference.
Could you point out what is problem and why it ocurred?
Additionally, I wish to know that the application above is compatible as Analog Voltage Input on ADS1298 or not.
Hi YoungSik Kim!
Are you trying to re-create the +/-2.5V supply we used for the ADS1298ECGFE-PDK that was created from a single 5V source or are you trying to generate an external reference?
I tried designing my own board.
I use DC to DC Converter, ±5V, and connect the Vsupply(Both + & -) on OPA735.
Also, The input of REF5025 is from DC to DC converter.
Here is the spec. I use:
I think that the DC Converter is not the origin of the noise, because the output of DC DC doesn`t generate such a wave pulse.
Moreover, the test board I made doesn`t connect any other chips: Except only DC Converter and the Application.
Have you ever gotten this worked out? I suspect the problem is related to the capacitive loading on the OPA735.
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