R

S

0.1 F

m

V+>3V

Load

-

16Vto+80V

Supply

Negative

and

Positive

Common-Mode

Voltage

I

L

A1

A2

Single-PoleFilter

Capacitor

5kW

5kW

96kW

R

L

PREOUT

BUFIN

GND

OUT

IN-

IN+

V+

INA270,INA271

74HC04

17

INA270, INA271

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SBOS381E – FEBRUARY 2007 – REVISED JANUARY 2018

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10 Power Supply Recommendations

The input circuitry of the INA270 and INA271 can accurately measure beyond its power-supply voltage, V+. For

example, the V+ power supply can be 5 V, whereas the load power-supply voltage is up to +80 V. The output

voltage range of the OUT terminal, however, is limited by the voltages on the power-supply pin.

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