Need Help: Updating Old Design With TinySwitch-II To Tiny Switch-4

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We have a product designed in 2002 using a TinySwitch generation II device (TNY267G) to make an 90-260 Vac input open frame/on a pc board 10 W isolated flyback power supply. We are updating this board for other reasons and while doing those updates we thought we would update to a newer power supply IC to avoid potential future obsolescence of the old part. From looking at the Power Integrations web site it looks like the TinySwitch generation 4 devices are the ones to use. Specifically for our supply it looks like we should use the TNY286D device.

In comparing data sheets for TNY267G and TNY286D it looks like the newer part has all the same functionality/operational characteristics of the older part except for a different pinout in the SO-8C package.

Our questions are:

1. Is TNY286D the right new part to replace TNY267G?
2. Other than pinout changes are there any other changes we should make to use TinSwitch-4 instead of TinySwitch-II?
3. Will we see any differences in the radiated EMI signature with the newer part compared to the old? For example, is the newer part faster and have higher dV/dt potentially causing more radiated energy?
4. Is there an app note about up grading from older to newer TinySwitch parts that we somehow missed?

To help be more specific I have attached our one page schematic for the existing supply using the TNY267G.

gby

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90-260_Vac_10W_Supply.pdf47.76 KB

Just bumping this post once to put at the top of the list again.

Really, 3 weeks and no one has help on differences between TinySwitch II and TinySwitch 4?

Hi gby,

Thank you so much for considering PI's product.
Regarding to your question, below are the replies:

1. Is TNY286D the right new part to replace TNY267G?
Is the power supply open frame or enclosed? Is your application for universal input?

2. Other than pinout changes are there any other changes we should make to use TinySwitch-4 instead of TinySwitch-II?
I would suggest you to use PI expert to calculate all the components required for using Tinyswitch-4, PI expert is a online tool from PI which helps you calculate all the component values for using our devices. Please use the link below for online PIExpert Tool:
https://piexpertonline.power.com/site/login

3. Will we see any differences in the radiated EMI signature with the newer part compared to the old? For example, is the newer part faster and have higher dV/dt potentially causing more radiated energy?
Regarding radiated EMI, since the pinout is different, the layout will be different. Therefore some EMI signature difference should be expected.

4.Is there an app note about up grading from older to newer TinySwitch parts that we somehow missed?
I would suggest using the online tool PIExpert for designing with Tinyswitch-4.

Please let me know if you have any further questions.
Thank you!

Tony, thanks for the reply.

As stated in the first line of my post this application is
"...an 90-260 Vac input open frame/on a pc board 10 W isolated flyback power supply"

Thanks for the pointer to PI Expert. I will check it out.

FWIW, we did buy some TNY286D parts and fly wired it into our old supply where the TNY267G was and at first look everything seemed to work fine. We will investigate with PI Expert and lab testing more.

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