10.1 Shutdown

The INA270 and INA271 do not provide a shutdown pin; however, because these devices consume a quiescent current less than 1 mA, they can be powered by either the output of logic gates or by transistor switches to supply power. Driving the gate low shuts down the INA270 and INA271. Use a totem-pole output buffer or gate that can provide sufficient drive along with a 0.1-μF bypass capacitor, preferably ceramic with good high-frequency characteristics. This gate must have a supply voltage of 3 V or greater because the INA270 and INA271 require a minimum supply greater than 2.7 V. In addition to eliminating quiescent current, this gate also turns off the 10-μA bias current present at each of the inputs. Note that the IN+ and IN– inputs are able to withstand full common-mode voltage under all powered and under-powered conditions. An example shutdown circuit is shown in Figure 22.

Figure 22. INA270–INA271 Example Shutdown Circuit