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I (think I) want to use an ITS4060S-SJ-N (+datasheet) in a circuit that can't handle over 40V (an LM2576T-5), but will normally receive 8-30V with a ≤12W load. Its purpose would be to provide overvoltage protection, short circuit protection, thermal shutdown, and reverse battery protection*. But I'm having trouble making sense of the datasheet to find what voltage it would clamp at. From the datasheet, I see that:

  • Overvoltage protection \$V_\text{SAZmin} = 41\text{V}\$ (Product Summary, p2)
  • Max supply voltage \$V_\text{S} = 40\text{V}\$ (Absolute Maximum Ratings, p5)
  • Overvoltage protection \$V_\text{OUT}=V_\text{S}-V_\text{ONCL}\$, \$V_\text{SAZmin}\$ = 41V (Electrical Characteristics, p8)
  • Output clamp at \$V_\text{OUT}=V_\text{S}-V_\text{DSCL}\$ (inductive load switch off), \$V_\text{DSCLmin}\$ = 41V (Electrical Characteristics, p8)

Does that mean it would clamp to 41V? \$V_\text{ONCL}\$ is only mentioned once, without further explanation. I've searched for \$V_\text{SAZmin}\$ online and couldn't come up with anything either. The \$V_\text{DSCL}\$ line seems to indicate that the output voltage is at least 41V lower than supply (\$V_\text{S}\$) under inductive load switch off, so perhaps that means that for say \$V_\text{S}<41\text{V}\$ then \$V_\text{OUT}=0\text{V}\$. But what constitutes the maximum output voltage? It could be anything up to 41V in that case. I think there would have to be something more in the logic block on p3...

* Will include a 150Ω ground resistor and a PMOSFET to limit load's reverse current, see note 4 on p8.

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So we have some ITS4060S-SJ-N, so I decided - why not just test it? Well, it passed up to 40V straight through to the OUT pin when the load drew around 20mA. That indicates that it won't disconnect the load if the supply voltage is too high. I suppose I would need something like http://www.ti.com/product/TPS2663 and the increased cost if I wanted that functionality. Oh well!

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  • \$\begingroup\$ It says overvoltage is 41V. So it would make sense it's still fine with 40V. \$\endgroup\$ – Jeroen3 Jun 11 at 5:52

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