TMUX6234: When powering up for the first time device goes into a high current mode.

• If the SEL (select) or EN (enable) pins are floating during power-up, internal FETs in the TMUX6234’s control logic may partially conduct, creating a high-current path from VDD to GND. This is common in CMOS switches when logic inputs are in an undefined state.
• Impact: This can cause excessive current draw (potentially mA to tens of mA) and prevent normal operation.                                                                                                     
• Add 47 kΩ pull-down resistors to SEL and EN pins.
• Verify power-up sequence: VDD first, then control signals.
• Check for pre-existing voltages on I/O pins; isolate if necessary.

Hi Paul,

The TMUX6234's sel/en pins have internal pull-down resistors, so you should not need to add any.

In looking at your layout, I wanted to make sure I'm oriented right - is pin 1 in the top left? If so, it looks like VDD/VSS might be switched.

Best,
Katy