Electronic – what is the difference between voltage output swing at no load vs at 10k load

datasheetoperational-amplifier

referring to page 6 of this op amp reference sheet under the heading "OUTPUT" http://www.ti.com/lit/ds/symlink/opa188.pdf

there are two output voltages – one for no load condition and one for 10k load condition. could someone provide me a circuit schematic so I can see where this load resistance is located? I'm new to designing op-amp circuits

Best Answer

A rail-to-rail output amplifier is designed to swing very close to the supply rails, unlike older op amps which sometimes couldn't get closer than a few volts.

However, there is a finite output resistance in the output stage, meaning you can't swing exactly to the rails. As the output stage starts to deliver current to a load the voltage drop across the output devices has to increase.

What the datasheet is saying is that with a 10K resistor between the output and ground, you are guaranteed to get within the specified voltage of the voltage rail on the output before saturating or clipping.

Lower resistance will result in a higher drop.