[theamk]

that seems like a real overkill - it's a full-blown RS232 receiver _and_ transmitter, including two DC-DC converters (with inductor and capacitor) that you don't even use... Also, "R_IN absolute max voltage" is +/- 25V, so I really would not use this in 24V system.

If you want slow and reliable input for industrial automation, it seems much safer to make one yourself - an input resistor, hefty diode/zener, voltage divider, maybe a schmitt trigger/debouncer made from opamp if you want to get real fancy.

[Certified]

Thanks for pointing that out. I realized I called out the wrong chip. I was actually trying to call out the Max6818.

[theamk]

That's a neat chip, especial max6816/max6817 version in SOT23 package!

but yeah, very expensive for what it does. If my MCU was really short on interrupts, I'd go with I2C bus expander with 5v-tolerant inputs and INT output - sure, it needs explicit protection for 24V operation, but it also only needs 3 pins and 1 interrupt.