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I am using 40x ICs INA301 to measure overcurrent in 40 interfaces Finally I want to have 1 single "output" to signal if there is an overcurrent in ANY of the 40 interfaces I don't want to utilize any uC for minimizing cost. I am right now using multiple 4input OR gates (cd4072, but I want to know if there is any clever circuit or IC that might do this minimizing PCB space/cost. Thanks in advance.

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  • \$\begingroup\$ Would you consider a diode OR gate made of discreet diodes? \$\endgroup\$ – Transistor May 4 '20 at 22:22
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Almost no components are required.

The INA301 datasheet says the ALERT pin is an open drain output, active low. This means that it is normally high impedance, and should be pulled up to Vcc with an external resistor. When the chip wants to signal an overcurrent, it pulls the line low using an internal transistor.

If you simply connect them all together, and share a single pull-up, then any one chip can pull the line low to indicate a fault. This will not affect the other chips. This is known as "wired OR".

You might need to tweak the pull-up resistor value a little to account for the leakage current. You definitely don't want one per chip, so don't just duplicate the recommended layout 40 times.

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  • \$\begingroup\$ Thanks for the answer, I knew there was a trick to do this. \$\endgroup\$ – Eduardo Ramírez Gómez May 5 '20 at 14:15
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Assuming you’re using the open-drain alert output, you can just wire them together with a single pull-up resistor (wired-or)- from datasheet.

enter image description here

If one or more /ALERT outputs go low then the wired-or common node will go low.

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