The OPAx591 use a unique input architecture to eliminate the need for input protection diodes but still provide robust input protection under transient conditions. The conventional input diode protection schemes in Figure 6-3are activated by fast transient step responses, and potentially introduce signal distortion and settling time delays because of alternate current paths; see also Figure 6-4. For low-gain circuits, these fast-ramping input signals forward-bias back-to-back diodes that cause an increase in input current and result in extended settling time.

Figure 6-3 OPA591 Input Protection Does Not Limit Differential Input Capability

Figure 6-4 Back-to-Back Diodes Create Settling Issues

The OPAx591 feature a true high-impedance differential input capability for high-voltage applications. This patented input protection architecture does not introduce additional signal distortion or delayed settling time, making these devices an excellent choice for multichannel, high-switched, input applications. The OPAx591 tolerate a maximum differential swing (voltage between inverting and noninverting pins of the op amp) of up to 85V, making these devices a great choice for use as a comparator or in applications with fast-ramping or switched input signals.