In typical split-supply operation, the midpoint between the power rails is ground. The midpoint at ground in a split-supply configuration is a valid operating condition for the OPA818 when using symmetric supply voltages that are greater than or equal to ±4 V. This configuration facilitates interfacing the OPA818 with common lab equipment that have inputs and outputs referenced to ground, such as signal generators, network analyzers, oscilloscopes, and spectrum analyzers. However, when using split-supply voltages less than ±4 V, ensure that the input common-mode range is not violated. Be aware that the typical input common-mode range of the OPA818 includes V_S– and extends up to 3.2 V from V_S+. For example, when using ±3 V supplies, ensure that the input common-mode voltage of the signal is typically 3.2 V from V_S+ and 3.6 V from V_S+, per the maximum specified input common-mode range. Ground is not included in the input common-mode range with ±3 V supplies, and results in erroneous operation if the input signal has ground as the midpoint. To prevent this issue, use +4/–2 V supplies.