cancel
Showing results for 
Search instead for 
Did you mean: 

e-fuse evaluation board question

RAlve.3
Associate II

Hello. I have a STEVAL-EFUSE01 board that uses the STEF01 e-fuse at its heart. I take it out of the package. I connect 24V to VCC_F (supply). I don't connect anything to the VOUT_F output. What voltage should I read on that output?

I think I should read 24V steady but it's pulsating. I have two STEVAL-EFUSE01 boards and both behave the same way so I can rule out board damage for now. What am I thinking that is wrong?

I saw a question on this topic before with no answer, hopefully someone will attempt to reply to this one.

Cheers

1 REPLY 1
RAlve.3
Associate II

I found that connecting GATE_M2 to GND will make the board behave exactly as expected at least on my setup.

Here's what I think is going on for future reference and in case someone can double-confirm:

On the STE01 datasheet there's an EN/ Fault pin table (table 7) that specifies that the output is ON when the pin is pulled high or low (excluding thermal fault conditions). GATE_M2 to GND is pulling EN/FAULT low and it works fine. Leaving GATE_M2 floating I thought would keep the EN/FAULT high (through internal pull up) but actually it leaves it unstable. So the pin is sometimes high (output enable) and sometimes low (output disabled) and the output is not steady-on as expected.