The OPA598 uses a unique input architecture to eliminate the need for input protection diodes but still provides robust input protection under transient conditions. Conventional input diode protection schemes shown in Figure 6-4 can be activated by fast transient step responses and can introduce signal distortion and settling time delays because of alternate current paths, as shown in Figure 6-6. For low-gain circuits, these fast-ramping input signals forward-bias back-to-back diodes that cause an increase in input current, resulting in extended settling time.

The OPA598 input protection does not limit differential input capability as shown in Figure 6-4 and Figure 6-5.

Figure 6-4 Conventional Input Protection Limits Differential Input Range

Figure 6-5 OPA598 Provides Full 85V Differential Input Range

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

The OPA598 has 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 this device an excellent choice for multichannel, high-switched, input applications. The OPA598 tolerates a maximum differential swing (voltage between inverting and noninverting pins of the op amp) of up to 85V, making this device a great choice for use as a comparator or in applications with fast-ramping or switched input signals.