The OPA140, OPA2140, and OPA4140 family has internal phase-reversal protection. Many FET- and bipolar-input op amps exhibit a phase reversal when the input is driven beyond the linear common-mode range. This condition is most often encountered in noninverting circuits when the input is driven beyond the specified common-mode voltage range, causing the output to reverse into the opposite rail. The input circuitry of the OPA140, OPA2140, and OPA4140 prevents phase reversal with excessive common-mode voltage; instead, the output limits into the appropriate rail (see Figure 6-21).