MC33078: MC33078DR performance problem.

Hi Yingjiao, 

MC33078 has internal ESD protection diodes on the outputs but these are not TVS diodes. Please see our video series on overstress protection for more information on external protection methods like TVS diodes: https://ti.com/video/4080379002001

Is there a reason there is a concern for the output protection for the MC33078? 

Regards,
Ashley

Hi

What about input port protection?

The input port has a clamp diode to the power rail

Hi Yingjiao,

Is this clamp on both of the inputs? Could you provide a schematic visual to show what you mean. 

And also, could you clarify what performance problems you are seeing with the MC33078? 

Thanks!
Regards,
Ashley

Hi  Ashley

We have described the corresponding problems in the following pictures, please help to confirm
thank you

.

Hi Yingjiao, 

Could you show what is on the output of U2A and U2B? When is the Vin waveforms during the power on sequence? During the first brief VCC increase? 

Regards,
Ashley

As shown in the figure,ch1 refers to In1+,ch2 refers to In1-,ch3 refers to In2+,ch4 refers to In2- of U2 during the power on sequence。

Hi Hongyao, 

To clarify, I am asking for the output pin waveform here: 

Also what is U1? 

Regards,
Ashley

Output waveforms of U1B and U2B during power on sequence are shown below

Hi Ashley,

   Thanks for your replying. I have no other questions temporarily.

   Thank you!

   Regards,
   Hongyao Liu