I have a question about AD7401
Is it okay to connect Pin4 to GND?
If it's connect to GND, what would happen?
*According to the datasheet, it says Pini4 to 6 treated as NC(Non connect)
Usually, NC means that the pin should be left open and must not be connected to anything during normal operation. However, this could mean two things, either the pin means no connection from the chip and if that's the case grounding the pin will not do any harm to the circuit or this could mean that the pin has an internal connection (mostly labeled as IC "internal connection") that may harm the device if connected to anything. For assurance, If there's no indication on the datasheet to which meaning of NC applies, these pins should be left unconnected or we can consult the Applications Engineer of the AD7401 for clarification.
Thank for your support , Jellenie.
I understand what you mean.
If it's okay with you, could you ask your application engineer about this?
Because TI have similar parts like the attached file, sometime I hear this kind of requests that they want to evaluate without design change.
And this is additional question, what if pin1(VDD1)? could you also check whether the pin1 is treated as NC like TI parts? like the attached file, AD7401 has two VDD1 pin.
Pin1 and pin7 are internally connected so you can supply the AD7401a via pin 7. However, please be aware that while the part is still functional, it cannot guarantee the performance since this is not how ADI tested it. Regarding the Pin 4, It can be connected to GND without any concerns.