UC1525A: UC1525AJ Re-Tinned Lead Plating

Miranda J

Part Number: UC1525A

Hi, my customer raised up a quick question on the plating for these modulator IC components as the leads appear to be re-tinned with a more shiny/brighter lead finish (see below). Customer is well aware that this is non RoHS version and has no issue with that.

DC: 2144A/ lot#: 1011770MTT/COO: Thailand

Is that a normal practice because of this particular package? or is it due to the parts are being non-RoHS and therefore re-tinned accordingly to improve the reflowing process?

Since the customer rarely sees the re-tinned parts (normally for repairing) and wonder if this question can have some further clarifications.

Thank you for your time reading this post.

Regards,

Miranda

8 months ago

0 Hong Huang 8 months ago

TI__Guru 57825 points

Hi,

It is to help avoid corrosion.

0 Miranda J 8 months ago in reply to Hong Huang

Intellectual 400 points

Hi Hong, thank you for the quick response. Could you share a bit more details, if there is any applicate note or explanatory information, so that I can explain with more information for the customer? Thanks again for your time.

Regards,

Miranda

0 Hong Huang 8 months ago in reply to Miranda J

TI__Guru 57825 points

Hi,

It was quite common with such material for semiconductor IC pins using SnPb for solder capability and reliability, and also corrosion resistance before Pb-free time. Sorry I cannot find application notes to particularly dedicated to explain why SnPb back to Pb-free manufacturing time. You can search the internet to look for some explanations before Pb-free product time such as why SnPb solder etc.

0 Miranda J 8 months ago in reply to Hong Huang

Intellectual 400 points

Hi Hong, I searched a bit and below is what I can find. Is this something similar to what you mentioned?

https://www.ti.com.cn/cn/lit/an/szza046/szza046.pdf?ts=1710198057915

https://www.ti.com/lit/an/szza035a/szza035a.pdf?ts=1710206729960&ref_url=https%253A%252F%252Fwww.google.com%252F

Thanks,

Miranda

+1 Hong Huang 8 months ago in reply to Miranda J

TI__Guru 57825 points

Hi,

The main reasons are solder capability, reliability and corrosion resistive capability before Pb-free time, quite commonly used. Why and how did it experience such evolution to come to the used SnPb? You would have to search more to find out. But a short answer is SnPb was popular and common for what I mentioned three main reasons in semiconductor IC industry for quite long time before Pb-free (RoHS and REACH compliance).

0 Miranda J 8 months ago in reply to Hong Huang

Intellectual 400 points

Hi Hong, appreciate your time answering my question.

Regards,

Miranda

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UC1525A: UC1525AJ Re-Tinned Lead Plating