NC pin of UC2844A

Thank you for your support!

How is your situation.

We hope earlier answer.

Best regards,

Takahiro Nishizawa

Hi Takahiro,

Nc Pin has no functional purpose to the outside circuit (but may have unexposed functionality). Those pins should not be connected to any of the circuit connections.

When deciding how to proceed with NC pins, consult the accompanying datasheet for explicit NC pin recommendations. While most manufacturers simply state that such pins should be left floating, in other cases they may have more specific recommendations such as connected to the ground rail for some additional, but unnecessary benefits.

IC chips are mostly mass produced in a limited array of package. Most designers are thus restricted to one of those pre-defined packages. Sometimes the device that's designed does not utilize all the pins for various reasons. It may also be as a result of post-package timming. Some manufacturers may also designate some pins for their internal use only (e.g. calibration or testing). When that happens, those pins gets labeled "NC" or "Not Connected".

Regards,

Teng

Thank you for your answer!

Please tell us your answer about question 1.

About Question 2,

Please tell us the reason why NC pin is not connected to any internal or external circuit.

Do you know the reason why We must not connect the NC pin and othr pins.

And Please tell us more detail about question 3.

We want to know if this IC has the risk when NC pin hits other pins contact in manufacturing process.

Best regards,

Takahiro Nishizawa

Thank you for your support!

How is your situation?

We are waiting for your answer!

Best regards,

Takahiro Nishizawa

Hi Takahiro,

I have answered your questions in my last response.

For your first question 1,

Yes, NC pin doesn't connect with other pins. But it may connect with internal circuit for possible unexposed functionality, some manufacturers may designate some pins for their internal use only (e.g. calibration or testing), which gets  labeled "NC" or "Not Connected".   It may also be as a result of post-package timming, sometimes the device that's designed does not utilize all the pins for various reasons. In this case, it doesn't connect with anything.

For question 2,

Please refer to question 1, NC pin can't connect other pins, because it may connect with internal circuit for possible unexposed functionality. Even if NC pin doesn't connect to internal circuit, the noise may be introduced if connect NC pin to other signal.

For question 3:

Please refer to last to question, yes there will a risk if connect NC pin to another pins. So recommend that when deciding how to proceed with NC pins, consult the accompanying datasheet for explicit NC pin recommendations.

Regards,

Teng

Thank you for your support!

We have question about UC2844A.

(UC2844ADTR)

 NC pin and other pin(COMP, FB, ISENSE, RT,CT) are next to each other.

We are concerned about the mistake of mounting in adjacent pins if NC pin is connected to other pin or internal circuit in mounting process.

For example,  wiring  will be connected to NC pin. It may result in malfunction or destruction.

Our customer has the concern to mistake the pattern or the mounting destination in mounting process.

So we want to check that NC pin is connected to other pin or not about UC2844A.

This concern disappears if NC pin of UC2844A is not connected to other pin and internal circuit.

We have question.

Please check if NC pin is not connected to other pin and internal circuit about UC2844ADTR.

Best regards,

Takahiro Nishizawa

Thank you for your support!

How is your situation?

We hope earlier answer!

We are concerned about the following.

Is NC pin of UC2844ADTR connected to other pin or internal circuit?

We are concerned that our customer mistakes pin connection in mounting process.

This IC will break down if NC pin is connected to other pin or internal circuit in IC when our customer mistakes pin connection in mounting process.

Best regards,

Takahiro Nishizawa

Hi Takahiro, I am checking this question with our designer. Regards——Teng