9.4.1 Split-Supply and Single-Supply Operation

The OPA858 can be configured with single-sided supplies or split-supplies as shown in Figure 63. Split-supply operation using balanced supplies with the input common-mode set to ground eases lab testing because most signal generators, network analyzers, spectrum analyzers, and other lab equipment typically reference inputs and outputs to ground. Split-supply operation is preferred in systems where the signals swing around ground. However, the system requires two supply rails. In split-supply operation, the thermal pad must be connected to the negative supply.

Newer systems use a single power supply to improve efficiency and reduce the cost of the extra power supply. The OPA858 can be used with a single positive supply (negative supply at ground) with no change in performance if the input common-mode and output swing are biased within the linear operation of the device. To change the circuit from a split-supply to a single-supply configuration, level shift all the voltages by half the difference between the power supply rails. In this case, the thermal pad must be connected to ground.