THS4551: TINA Simulation error

Hi Shmuel,

by decreasing RG1 and RG2 you increase the gain of THS4551 too much and drive the output into saturation:

Kai

Dear Kai,

Thanks for your quick reply.

If the gain is to high then why do I get the same error when I set the input to 0.1V instead of 1.25V ?

Regards 

Shmuel 

Hi Shmuel,

where do you have 1.25V?

Kai

Kai

Kai

"where do you have 1.25V?"

Within IO01_n

The simulation should have passed with 0.1V input without changing the resistor values (305 -> 351) like you did no ?

shmuel_ths4551.TSC

Kai

?????????

Hi Shmuel,

it's a known (and a bit annyoing) fact that the simulator is instable from time to time. In most cases it can be fixed by modifying the parameter settings in the "Set Analysis Parameters" menue. But it's faster to change the component values of schematic a bit :-)

Kai

Well Mr. Davis, 

I also have had this experience with numerous TINA device models. Annoying to say the least, but I have usually had good luck changing the analysis options to the following, 

And simplifying the circuit can help a lot, Shmuel.

Divide your circuit into modules and simulate them individually. There's no need to put even the smallest screw into the simulation.

Divide and conquer :-)

Kai

Dear Michael,

Thnaks for your help !

I changed to Trapezoidal in the Transient options - but I don't have the option for Matrix solver for some reason ? I tried it but I still got the same error !??

Best Regards

Shmuel

Dear Kai,

"it's a known (and a bit annyoing) fact that the simulator is instable from time to time. In most cases it can be fixed by modifying the parameter settings in the "Set Analysis Parameters" menue. But it's faster to change the component values of schematic a bit :-)"

Which parameter settings in the "Set Analysis Parameters" menu should I alter ? 

I can't change the component values as I am trying to test these specific paramters !

Shmuel

I am using V11, maybe your free version does not have the matrix solver option. 

Insert the file as you want it, and I will see if I can run it. 

Hi Shmuel,

it's a bit "trial and error" to find the best parameters settings. So, unfortunately, I cannot answer your question. But you can give these "crash" settings a try:

And, last but not least, you can go to the manufacturer's site of TINA-TI (DesignSoft) and ask for help.

Kai

Hello Shmuel,

It is also worth noting that you are using the 2016 version of the THS4551 model. If you would like to get the transient analysis to work with that model specifically, you can try different preset analysis settings such as Kai has shown in the last post. The Davis's KLU method as Michael suggested doesn't seem to be available in the free version of TINA.

I've attached your circuit with the latest THS4551 model which doesn't run into the same issues.

CCT2 - S2 for Forum_updated.TSC

Best,

Hasan Babiker

Also Shmuel, 

One of the reasons you might be having  a transient sim issue is the loop gain phase margin sim for your circuit shows unstable, 

I tested all 3 model versions I know about and they are all just past 180deg around the loop at LG=0dB crossover, The inserted article talks about fixing these things, 

Final THS4551 stage phase margin tests with different models.docx

In addition...

shmuel_ths4551_1.TSC

Kai

Oops!! The file I had modified to test phase margin had a 1nF across the FDA input pins, if I remove that - your circuit is fine, with >90deg phase margin. Sorry about that.