Understanding why an OPA27 is unsuitable for a window comparator and a MC1458DR is better
Understanding the datasheet specs incl. Absolute Maximum and schematic is essential, takes time and well worth the effort.

The lack of input resistance reduces noise and the clamping of inputs protects them from damage as Vbe = -5V reverse max. But it is possible to protect the inputs other ways allowing +/- 30V differential input.