The shutdown (enable) function of the OPA1633 is referenced to the negative supply of the operational amplifier. A valid logic low (< 0.8 V above negative supply) applied to the Enable pin (pin 7) disables the amplifier output. Voltages applied to pin 7 that are greater than 2 V above the negative supply place the amplifier output in an active state, and the device is enabled. If pin 7 is left disconnected, an internal pullup resistor enables the device. Turn-on and turn-off times are approximately 2 μs each.

Quiescent current is reduced to approximately 0.77 mA when the amplifier is disabled. When disabled, the output stage is not in a high-impedance state. Thus, the shutdown function cannot be used to create a multiplexed switching function in series with multiple amplifiers.