ALERT

Alert

Output

ALERT

CMPREF

CMPIN, VOUT

4 V

Vs

4 V

VOUT

RESET

ALERT

VS+

GND

CMPIN

CMPREF

10 k:

+

±

+

±

G = 20, 50,

100, 200

5 V

2.7 V to 5.5 V

INA381-Q1

REF3140

4 V

0.2% , 15ppm/°C

VS+

16

INA381-Q1

SLYS041 – MARCH 2020

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Feature Description (continued)

The device determines if an overcurrent event is present by comparing the voltage on the CMPIN pin to the

corresponding signal developed at the CMPREF pin. The threshold voltage for the CMPREF pin can be set with

a resistive divider, or by connecting an external voltage source (such as a reference generator device). Figure 43

depicts the REF3140 used as an external reference source.

Figure 43. External Reference Voltage

7.3.6 Comparator Hysteresis

The onboard comparator in the INA381-Q1 is designed to reduce the possibility of oscillations in the alert output

when the measured signal level is near the overlimit threshold level as a result of noise. When the voltage

voltage must drop to less than the CMPREF pin threshold voltage, as shown in Figure 44, by the hysteresis level

of 50 mV so that the ALERT pin deasserts and returns to the nominal high state. The INA381-Q1 is designed

with a hysteresis of 50 mV.

Figure 44. Typical Comparator Hysteresis