TMUX1109: Inrush Current Spec for IO pin

Hi Jim,

There are a couple of things you need to consider for this.

What temperature are you running the device at? The max current spec is rated at max temp, so depending on the operating temperature and the magnitude of the current in-rush you may not actually violate max current because that spec becomes a little bit more loose if you aren't maxing out temperature.

That being said, the only sure fire way to protect the mux, is to place a current limiting series resistor that will limit the current to < 30mA. The tradeoff here is that you are now going to have more loss across the limiting resistor. 

Please let me know about the operating temp and the magnitude of the in-rush so I can get you a more specific answer.

Best,

Parker Dodson

Hi Parker,

Thanks for the reply.

Share the inrush waveforms as CH1 in pictures.

-          The max inrush we saw is 0.55A/ 88uS in room temperature (25 ^OC)

-          TMUX1109 will work at 40 ^OC and 50 ^OC for different products.

Please help to check if it is ok or not.

Thank you.

Regards,

Jim

Hi Jim,

That is a large inrush current, and it would be best to try to limit it to avoid part damage.

What does the load look like? I.e. What does the impedance look like at the load because a current limiting resistor may not degrade the signal too much. But with over 10x the spec'd current at inrush I would be a bit worried about part damage, even if you aren't operating at full temperature.

Also if I could ask, what does the customer or you would feel would be good way to spec in-rush current support, it isn't something we typically do, but it something we can look into the future.

Best,

Parker Dodson