Strange High Side Switch behaviour / VN751PT

[CedTra]

HI!

We have from time to time defect High Side Driver. Most of the defects occur after the first few power on cycles. 

The High Side Driver and the RGND Resistor (120Ohm) gets really hot. The resistance between GND and the Status Pin is then much lower around 160Ohm to 2kOhm instead of 12kOhm. 

Might it be a Problem when there is only the 24V Power Supply and the Status / IN Pin has no reference Voltage? 

There are cases when the 5V comes later or not. Does this destroy the internal Logic Circuit? 

Did somebody had some similar defects?

Any help is much appreciated.

THX

[Peter BENSCH]

You probably intended to use RGND to protect the device in case of reverse polarity, correct?

If the device becomes very hot and the status pin has low resistance, apparently wanting to output a low signal, this indicates overtemperature.

Could it be that an excessive load was applied to the output at this point or that a short circuit was caused?

Regards
/Peter

[CedTra]

Hi Peter

Acutally the original schematic did not I made. So I cant tell you what the real reason behind the RGND Resistor ist. Because the device has a 24 Input Polarity Protection. So there will never be reverse polarity. 

And we have defect High-Side Drivers after soldering without ever swtiching a big load at the output. 

Kind regards

Cédric