Opamp Pins Labeled NULL

[skipwave]

I'm working with the LT1363CN8. I've used the quad version before, which doesn't have the NULL pins that I'm inquiring about. Here's the datasheet: http://www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1154,C1009,C1022,P1108,D3603

What are pins 1 and 8, labeled NULL, intended for? On Page 9 of the PDF linked to above, under Applications Information is a little schemo labeled Offset Nulling.

Thanks in advance!

 

[bcarso]

By hooking a potentiometer up as shown the initial offset voltage at the op amp inputs can be adjusted to zero. You will probably be interested in making the output voltage d.c. value zero, so you will be looking at that and adjusting the pot to zero it.

In practice with moderate impedance resistor networks around the amp for setting the gain, there will also be an output offset voltage contribution from the bias currents at the amp inputs, so you will be adjusting the potentiometer to set the output voltage at zero and compensating for both the offset voltage and the bias current error effects.