This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

UCC256303: Design Concern of UCC256303 compatible with UCC256403

Part Number: UCC256303
Other Parts Discussed in Thread: UCC256403

Dear TI,

My team is now using UCC256303 as HB LLC controller.

I've notice that there's a update version which is UCC256403, one of the major different between them is minimum detectable slew rate(303=1V/ns and 403=0.1V/ns).

However some suggestions in the forum for fixing UCC256303 failure are replacing it with UCC256403.

So there're my questions:

1. if my team insist to use UCC256303, Is there any further peripheral circuit design suggestion or operation notice if we want the 303 behavior as good as 403 

2. Advantage and disadvantage of UCC256303 and UCC256403, what are the benefits if we use UCC256403?



  • Hi Theoleslie,

    We strongly recommend using UCC25640x instead of UCC25630x since 40x has much improved features.

    The UCC256403 contains the same pinout as the UCC256303 and should only require minimal component value changes around the IC.

    This application note summarizes the key differences between the UCC25630x and UCC25640x controller families: 

    They major differences between the UCC256303 vs the UCC256403 is an improved slew rate detector capable of detecting slew rates down to 0.1V/ns (1V/ns for UCC256303) and greater flexibility to control the soft start behavior of the LLC converter through adjustment of the ssinit voltage before switching begins.


    You cannot add any external circuitry to the 303 to make the performance same as 403. 


    Manikanta P

  • Hi Manikanta,

    Thanks for your illustration, we're currently utilizing the UCC25640x Design Calculator, we'd like to know the calculation formula but the spreadsheet required a password to edit the cell. Can we ask for the password to unlock this? 



  • I had shared the password through e2e direct message. So, I am closing this thread.


    Manikanta P