Output impedance/resistance of a op-amp follower - data sheet

[Chris_PL]

Hi to all helpful souls,

Being a semi-pro on digital side of things I'm a complete newbie to analog design (on a hobbyist level), esp. when it comes to interpreting gazillion of values on analog parts data sheets.

The question is - I need to roughly estimate the output resistance/impedance of an op-amp configured as gain=1/buffer/follower. There's a voltage divider at the output using 0.1% resistors, so I would like to know where to look on the data sheet/what to calculate from it, so I could tweak the "upper resistor" value of the divider to be overall as close to "exactly what I want" as possible?

Or maybe the "low output resistance" in op-amp theory means in real world parts really, really low, in the order of single Ohms, not let's say tens or hundreds of them?

Signal is pretty low frequency, let's say DC to 100Hz tops. And yes, I know that hooking any load on the output of divider would mess it somewhat, but the load is known, so there's no problem with that part.

[w2aew]

Hi to all helpful souls,

Being a semi-pro on digital side of things I'm a complete newbie to analog design (on a hobbyist level), esp. when it comes to interpreting gazillion of values on analog parts data sheets.

The question is - I need to roughly estimate the output resistance/impedance of an op-amp configured as gain=1/buffer/follower. There's a voltage divider at the output using 0.1% resistors, so I would like to know where to look on the data sheet/what to calculate from it, so I could tweak the "upper resistor" value of the divider to be overall as close to "exactly what I want" as possible?

Or maybe the "low output resistance" in op-amp theory means in real world parts really, really low, in the order of single Ohms, not let's say tens or hundreds of them?

Signal is pretty low frequency, let's say DC to 100Hz tops. And yes, I know that hooking any load on the output of divider would mess it somewhat, but the load is known, so there's no problem with that part.

The negative feedback, closed loop effectively makes the output quite low (because the output adjusts to whatever's necessary to null the input voltage difference). Of course, there are output current limitations, and that is certainly in the data sheet.  What is your load impedance.