The OPAx197-Q1 use a unique input architecture to eliminate the need for input protection diodes but still provide robust input protection under transient conditions. Conventional input diode protection schemes shown in Figure 7-1 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 7-2. For low-gain circuits, these fast-ramping input signals forward-bias back-to-back diodes, causing an increase in input current, and resulting in extended settling time, as shown in Figure 7-3.

Figure 7-1 OPAx197-Q1 Input Protection Does Not Limit Differential Input Capability

Figure 7-2 Back-to-Back Diodes Create Settling Issues

Figure 7-3 OPAx197-Q1 Protection Circuit Maintains Fast-Settling Transient Response

The OPAx197-Q1 family of operational amplifiers provides 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 the optimal op amps for multichannel, high-switched, input applications. The OPAx197-Q1 tolerate a maximum differential swing (voltage between inverting and noninverting pins of the op amp) of up to 36 V, making these devices an excellent choice for use as comparators or in applications with fast-ramping input signals, such as multiplexed data-acquisition systems; see Figure 8-1.