What is the impedance of AD5560 output impedance & sense input impedance per V/I ranges?

Hola, Stitch.

We unfortunately do not spec these parameters you are asking for but we got a datasheet plot and a line in the spec that can help give an idea on how much input/output impedances you can expect.

For the sense input behavior, you may refer to this plot (refer to the red line), and it is not dependent of the current range:

For the output impedance, this DC regulation spec may help you ballpark:

This can suggest that load regulation somehow scales with current range. You can expect for these values to go down as you go to lower ranges.

There are currently no plans to spec the impedance values you are asking for but this is the best shot for now to describe these pins' behavior.

Best regards,
Mac

Hola, Stitch.

We unfortunately do not spec these parameters you are asking for but we got a datasheet plot and a line in the spec that can help give an idea on how much input/output impedances you can expect.

For the sense input behavior, you may refer to this plot (refer to the red line), and it is not dependent of the current range:

For the output impedance, this DC regulation spec may help you ballpark:

This can suggest that load regulation somehow scales with current range. You can expect for these values to go down as you go to lower ranges.

There are currently no plans to spec the impedance values you are asking for but this is the best shot for now to describe these pins' behavior.

Best regards,
Mac

Hola Mac

Could you help me understand how to convert those plot into sense input impedance?

Regarding to the DC load regulation, so the output impedance is 1K ohm for EXT 1A range & 0.8K ohm for EXT 0.5A range?

could you also share the DC load regulation for internal ranges?

Hola, Stitch.

Because we do not spec sense input impedance, I can't tell you with certainty that this is going to be a one-to-one correlation. However, you can ballpark sense input impedance by getting the change in stress voltage divided by the change in leakage current.

For example, refer to the red plot at 5V/ and -5V:

Z = (5V-(-5V)/(0.07nA-(-0.125nA)) = 1.8Gigaohm

To use DC Load regulation, example for EXT Range 1:

Z = 1mV/1A = 1milliohm

We don't have the specs values for the DC Load regulation for lower current ranges. I think the reason is that in the external ranges, it can be implied that output impedance is already low enough. Load regulation is also expected to go down with the current range.

But once again, I would like to emphasize that the calculations above may deviate from the actual input and output impedances. I think, however, that they are enough to demonstrate that these values are very high and very low, respectively, as expected.

Best regards,
Mac

Hola Mac

Regarding to your calculation, it is for single-end.  If I am not wrong, sense input impedance is in differential.  How to convert single-end data into differential data?

Hola, Stitch.

The calculation I gave above should not be interpreted as if saying that the input impedance of AD5560's sense is indeed 1.8GOhms. This is only to provide an insight on how it can be thought of or ballparked. There may be other things that can affect impedances and the actual impedance may be far from 1.8Gohms. I can't know for sure without characterizing the part because it wasn't specified in the datasheet. In line with this, I also cannot give a recommendation on how single-ended impedances can be translated to differential in this case. Also, there are no plans as of this writing to characterize impedances of the sense and force pins of AD5560.

Best regards,
Mac