[Buffering an Op Amp.TSC]

Driving a heavy (low impedance) load with a precision op amp sacrifices the very parameters that you paid for: offset voltage, drift, bias current, and, of course, MTBF due to high junction temperatures caused by power dissipation. By adding a buffer
amplifier between the op amp and its load places the burden of driving the heavy load on the buffer-- just what it was designed to do. The power dissipation is placed upon the buffer, allowing the op amp to deliver the precision it was selected for.