The OPA593 incorporates an enable and disable feature that uses the E/D pin to disable the output stage of the amplifier, which reduces the power consumption of the op amp and switches the output to a high-impedance state.

The E/D pin is referenced to the E/D Com pin. If left floating, the E/D pin is internally pulled up to enable the device. If externally controlled, the E/D pin must be supplied with a voltage between 1.5 V and 5.5 V greater than the E/D Com pin voltage. Even though the OPA593 output is enabled with a floating E/D pin, a moderately fast, negative-going signal capacitively coupled to the E/D pin can overpower the internal pullup and cause device shutdown. If the enable function is not used, a conservative and recommended approach is to connect E/D through a 47-pF capacitor to E/D Com. Figure 7-3 shows different ways to connect the E/D and E/D Com pins.

When the E/D pin is dropped to a voltage between 0 V and 0.5 V greater than the E/D Com pin voltage, the output of the OPA593 is disabled. When disabled, the output of the OPA593 is set to a high-impedance state.