TMUX1134: TMUX1134 Source Pin status when device is not powered

Kelvin Ng

Part Number: TMUX1134

I've use TMUX1134 on one board and have several source (S1A, S2A, S3A, S4A) pins branch out to a connector that connect to a separate power board. The power board would turn ON first before powering the board with the TMUX1134. From the power board perspective, what's the state of those source pins if TMUX1134 is not powered? Should it be High-Z or something else?

over 2 years ago

0 Clemens Ladisch over 2 years ago

Guru 318050 points

There is no powered-off protection on these pins. There are internal ESD diodes to V_DD; the absolute maximum ratings forbid voltages above V_DD + 0.5 V.

0 Kelvin Ng over 2 years ago in reply to Clemens Ladisch

Prodigy 30 points

So it would look like an input with internal diodes to VDD and GND or just VDD?

+1 Clemens Ladisch over 2 years ago in reply to Kelvin Ng

Guru 318050 points

There are always diodes from GND. (But you would never apply negative voltages, with or without power.)

When unpowered, the diodes create a low-impedance connection to V_DD. So applying a voltage can partially power up the switch and any other devices connected to V_DD.

Switches & multiplexers

Switches & multiplexers forum

TMUX1134: TMUX1134 Source Pin status when device is not powered