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INA302-Q1: Alert2 pin not recovered

Part Number: INA302-Q1

Dear sir,

INA302A1 current sensor we are used for current measurement and short circuit protection to battery. We are provided differential input to sensor under normal operating condition less than 125mV, but during short circuit condition sometimes differential input crosses above 125mV. 

we are operating INA302A1 current sensor in latch mode with 5V power supply. alert2 pin contains pull up high externally.

While short circuit happens the alert2 pin becomes active  low and it protects battery from excess current. But  After short circuit condition is over, alert2 pin is not reached pull up high even-though latch2 pin pull down for 100ns to 1ms.

This problem also randomly came, But once reset power of INA302A1 then alert2 pin becomes active high.

  • Santhosh,

    This looks like a duplicate of your original post. Please see our engineer's reply here.

  • After short circuit period is over, vout pin of INA302A1 is shown vref value only and current also zero.

    But alert pin not recovered in  very rare situation even-though latch pin pull down low for 100ns to 1ms.

    But we are suspecting that during short circuit If vout crosses IC power supply voltage (Vs), it is impacting anything inside IC latch pin functionality circuit. Because of that reason alert is not recovered even-though latch pin pull down from 100ns to 1ms (after short circuit is over) whether we are suspecting correct way or not please explain.

    Waveforms are unable to captured during that period very randomly occur. But one thing we are sure power on reset to IC every-time clear alert status from low to high (when alert is not recovered after short circuit period is over).

    For clearing short circuit what was maximum time required for latch pin pull down in datasheet not mentioned?

  • Santhosh,

    As Guang mentioned in your other forum post, a good candidate for the issues you are having is that the comparator has a built in 100mV hysteresis to avoid jitter on the ALERT output. Are you ensuring that the test condition you are examining is able to recover beyond the hysteresis point when you reset the line?

    Regarding the timing of the RESET pin, as the datasheet specifies, the minimum time is 100ns to properly clear the line. The reason the datasheet does not specify a maximum is because there is no maximum. When the RESET pin is asserted, it does not kill the line, but instead moves it to :"transparent mode." In this mode, the ALERT pin will track the states rather than simply latching up as it does in latch mode. There is an image to help visualize this mode in the datasheet:

    You mention that after this event, the output voltage is "Vref value only." What are you implying as the value of Vref here? Also, can you share your schematic?