Problems with Tin on QN9021 and FXTH87EH11DT1

[liyuntong]

Does anyone know if the pins on the side of the NXP QN9021 chip and FXTH87EH11DT1 chip need to be tinned? What are the risks if there is no tin? Is there any passivation on the pins on the side of the chip? Friends who know the answer, please leave a message, I am grateful!

[JozefKozon]

Dear Tony,

the pins on the case are already tinned in production process. If you connect or don't connect the unused pins on the board, there is no difference in the function of the chip, but the unused pins should be connected to the board mainly for mechanical reasons (the chip holds better on the board). 

So as the conclusion. On the board should be a small spot for every unused pin and every pin should be soldered to the appropriate spot.

With Best Regards,

Jozef

[liyuntong]

Thanks a lot for your reply！

But what I meant is the pins on the side of chip as the picture below.So,do you know if the pins inside the red box need to be tinned?

If your know the answer,please tell me.Looking forward to your reply.Thank you so much!

[JozefKozon]

Dear Tony,

I have sent the question to an application engineer dealing with the tire pressure sensors and she has answered, that the picture doesn't correspond with the FXTH87EH11DT1 package. Is the picture for the QN9021? Please see the description.

DESCRIPTION

The chip on the picture does not look like the FXTH87EH11DT1 chip, the FXTH does not have side pins like that. Could you confirm with the customer whether the follow-up question on the side pins is for the FXTH or the QN9021? I don’t know the QN products so I am not able to answer for them.

With Best Regards,

Jozef

[liyuntong]

Dear Jozef,

Sorry to cause misunderstanding.That picture is not a tire pressure chip, it is just an example. The picture below is the tire FXTH87EH11DT1 chip, please check .Thanks for your help!

Best  regards!

[JozefKozon]

Dear Tony,

the application engineer has sent an answer to the question regarding the pads on the side of the chip. Please see the description and pictures attached.

DESCRIPTION

Assembly guidelines for QFN packages (TPMS package) are detailed in this App Note. The terminal ends of the FXTH are with side wettable flank so follow the recommendation below:

A visual is given in Figure 10:

With Best Regards,

Jozef

[liyuntong]

Dear Jozef，

Thanks a lot for your reply！

But what I meant is the pins on the side of chip as the picture below.So,do you know if the pins inside the red box need to be tinned?

If your know the answer,please tell me.Looking forward to your reply.Thank you so much!

Best regards!