It really is LM108 and LM112 (internally compensated) and there is actually no trick there. It's got 1nA enter bias and that is relatively secure with temperature as in most bipolar opamps because β in fact improves with temperature. Afterwards iterations like LT1008/LT1012 or OP97 pushed it down to A https://low-noise-amplifier58023.ka-blogs.com/87443500/coaxial-switch-things-to-know-before-you-buy