SLG59M1440V Startup Glitching

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phunter9
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Last seen: 3 years 4 months ago
Joined: 2019-04-16 00:45
SLG59M1440V Startup Glitching

Hello,

I am driving a SLG59M1440V with 3.3V rail on D/Vin, and transitioning from 0V to 3.3V driven through an 86.6K resistor to the ON pin.

I observe the S/Vout ramping up to approximately 3V before falling with an RC decay to nearly 0.5V.  This cycle occurs a random number of times before the output ramps successfully up to 3.3V and stays.

It appears that the switch is toggling on/off.  During this event, I have probed the ON pin and it is held at around 1.1V for the duration of the cycling, and rises to 3.3V once the output rises to 3.3V as well.  All the while the 3.3V is constant on the D/Vin pin and on the other side of the 86.6k resistor.

Can you please help me understand what is going on and what could be causing this behavior?

In the attached file:

  • Green is D/Vin = 3.3V
  • Magenta is Signal on 86.6k resistor = 3.3V
  • Yellow is ON pin = 1.1V
  • Blue os S/Vout pin = Glitching from 0.5V->3.0V

Thank you,

Scott

Attachment: 
Device: 
Device Number: 
SLG59M1440V
Petro
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Last seen: 1 year 11 months ago
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Joined: 2018-10-02 07:43
Hi Scott,

Hi Scott,

Thank you for your question. The 1.1V that you see on ON pin is normal behavior. In this part the Slew rate is set through the current to the ON pin through series resistor. Internal reference voltage is 1.05V, so that is why during power up you see that voltage is around 1.1V and then after power up the voltage rise to 3.3V (your logic level). Regarding VOUT behaviour, so what is you resitor load and capacitance on VOUT? Based on the scopeshot it looks like internal thermal protection is triggered. Can you show a piece of you schematic with components around the 1440? Also, can you just try to power up 1440 without any CLOAD and RLOAD and see if this issue is still present?