UC2825: Is there technical difference inside between Q1 and EP grade

Hi Richard,

For Question 1 I need to ask some one familiar with the EP version of the part as it is outside of our specific portfolio. Give me a day or two to respond.

Question 2. I need to check with the factory.

Question 3. I see what you mean, in push-pull you can still get a 100% duty cycle from each output but with respect to the clock each output can only be on for a maximum of 50% of the time.

Regards

Peter

Any progress?

Does the UC2825A has actually have build in thermal shutdown without mentioning in datasheet, I found this behaviour consitence to thermal shutdown from other PWM controller, ie had to reduce to 130C to clear thermal shutdown flag after 165C event.

Hi Richard,

I just noticed that I had not replied to your post but I remember writing the response but it never got posted.

There may be some differences in the electrical tables between the EP device and the Q1 device. The EP team may change the limits to account for variations due to the different environmental conditions.

I have ask the EP BU to help with your questions on the package history.

Ignore the TI think resolved I hit it accidentally and I cant undo it.

Regards

Peter

There are some documents located here : www.ti.com/.../technical-documents.html
That discuss the Enhanced Products (-EP) flow and devices.
Other than these flow differences, the only difference between these two devices is the temperature extension. This is not necessarily true for all EP vs Q1 vs standard catalog devices.

Regards,
Wade

Sorry, I forgot to answer the package question. Yes, there have been package changes to this device in the past 20 years.
Regards,
Wade

Thank

However after bit of reading I could not make sense in relation to thermal shutdown behaviour which seems to have an undocumented feature in UC2825A from Q1 and EP. This is a specific question in mind I would like to address that. ie, have they modified the circuit at the dies level?

In regard to temperature extension, do you have a specific answer to?

Looking ahead related to a future project, is there digital power solution to replace UC2825A (for push-pull) that work at 125C and 150C?

Kind regards

R. 

  

Hi Richard,

You are correct I cant find any reference to thermal shutdown as a feature in the Q1 or EP datasheets and I have asked the design team if there is a feature in the part that performs this function.

I believe the temperatures extensions Wade if referring to are the extremes of operating ranges that the electrical characteristics cover. I expect there may be some differences between EP devices and Q1 devices on a part by part basis.

From the HVP product line perspective there is no equivalent digital solution that will work at 125C to 150C to replace the UC2825A.

Is the higher operating temperature the primary consideration for a new version of the UC2825A?

Regards

Peter

Please let me know the outcome of the thermal shutdown question from your team (feature creep?).
Yes we looking for higher temp based on UC2825A and if possible optimised to work GaN, ie higher clock freq for smaller package rather than change of GaN driver (internally,would be nice if they do). The other option is digital PWM for better slope compensation.

Hey Richard,

There shouldn't be any change in thermal shutdown between Commercial, Q1, and EP parts.
If you are seeing a 165 thermal shutdown on the UC2825A then it is likely going to effect the Q1/EP parts.

Thanks,
Daniel

Hi Richard

The IC design team have checked the schematic and they cannot find any evidence of an undocumented thermal shutdown feature. They have a couple of questions below which may help them identify what is going on.

Do you exactly know what happen at 165°C, when the “device shuts down”?
Does only the switching stop?
Is the SS pin discharged?
Does the reference go to 0V?

Usually the OTP, when present, is managed as a fault so it shouldn’t switch off the VREF.

Regards

Peter

Hi

I only just relocates to Canada so my lab is not ready, this test should really be bored by a producer, however I will check this out.

I do not wish to share result in this forum, shall we set up private comm via email: rpayne@arrivaloiltools.com 

R