TINA/Spice: Current Sense Amplifiers for 1mA to 1A

Andrew Buckin

Expert 2130 points

Other Parts Discussed in Thread: TINA-TI, INA301, INA169, INA233, INA240

Tool/software: TINA-TI or Spice Models

Hello all, help to choose Current Sense Amplifiers for the range 1мА - 1А.

Rsene is not larger than 1R. Better than less than 1R.

Thank you.

Andrew.

over 8 years ago

0 Nikhil Gupta (Product Folder Models) over 8 years ago

TI__Mastermind 39210 points

Hi Andrew,

Consider utilizing the following page: www.ti.com/.../products.html which should help narrow down your search. Also, when you click on any product to go to their respective product pages, you can see the error chart v/s current as well to help narrow down your selection. I hope this helps.

0 Andrew Buckin over 8 years ago in reply to Nikhil Gupta (Product Folder Models)

Expert 2130 points

Thank you,

I did not find the INA301 and considered the variant with the INA169.

But, the INA169 has Offset voltage 1mV. :(

Andrew.

0 Carlos Silva85 over 8 years ago in reply to Andrew Buckin

TI__Expert 4915 points

We have some digital parts with an offset very close to zero. The INA233 is a good example of one such part with a typical offset of 2.5uV

Our lowest offset analogue part is the INA240, it has an offset of 25uV and 0.05uV/C variation with temperature.

The INA301 is just a bit higher. We have spice models here

0 Andrew Buckin over 8 years ago in reply to Carlos Silva85

Expert 2130 points

Thank you,

I do not need a digital Output.

Is PSpice Moles of INA301Correct?

Andrew.INA301.TSC

0 Carlos Silva85 over 8 years ago in reply to Andrew Buckin

TI__Expert 4915 points

For analogue output the INA240 and INA301 are our lowest offset devices.
The PSpice model should be correct. Are you having any issues?

0 Andrew Buckin over 8 years ago in reply to Carlos Silva85

Expert 2130 points

Yes, I'm having problems. The output of INA301 is not linear.

0 Carlos Silva85 over 8 years ago in reply to Andrew Buckin

TI__Expert 4915 points

Thank you for sharing this.
The output definitively doesn't appear correct.

Let me check this with the model team and I will get back to you.

0 John Miller - Sensing over 8 years ago in reply to Andrew Buckin

TI__Mastermind 40295 points

Carlos,
I will take a look at your circuit and let you know what I find.
Regards,
John

0 John Miller - Sensing over 8 years ago in reply to John Miller - Sensing

TI__Mastermind 40295 points

Andrew,
The output glitch is being caused by the internal op amp model struggling to recover from an output overdrive condition. I'm not sure yet how long this will take to fix and will give a time-line by Thursday or Friday.

Regards,
John

0 John Miller - Sensing over 8 years ago in reply to John Miller - Sensing

TI__Mastermind 40295 points

Andrew,

The internal op amp's voltage-limiting circuitry is having trouble recovering from output saturation at either rail.
It eventually recovers, but the time delay leads to the output glitch.

I am not sure how long this will take to fix, but I will give an update next Wednesday, 8/23.

The same block is used in some other models, so the fix we come up with here will propagate to those models as well.
Thanks for taking the time to point out this issue.

Regards,
John

0 Andrew Buckin over 8 years ago in reply to John Miller - Sensing

Expert 2130 points

Thank you John,

I can finish the development in September. :(
Holiday time.

Regards,

Andrew.

0 John Miller - Sensing over 8 years ago in reply to John Miller - Sensing

TI__Mastermind 40295 points

Andrew,
Some other priorities have kept me from working on this.
My schedule should clear up in the next few days.
I will let you know the status early next week.
Regards,
John

0 John Miller - Sensing over 8 years ago in reply to John Miller - Sensing

TI__Mastermind 40295 points

Andrew,

I had to set this aside for a few days due to some other modeling issues..
Those should be completed by the end of this week so I can return to this on Monday, hopefully having an updated model for you by Tuesday or Wednesday.

Apologies for the delay.

Regards,
John

0 John Miller - Sensing over 8 years ago in reply to John Miller - Sensing

TI__Mastermind 40295 points

Andrew,

I think we might have a solution to the problem you have experienced with the INA301A1 model.
Please look at the attached circuit and let me know whether or not the revised model is okay.

Thank you for finding this and taking the time to point it out.

Regards,
John

INA301_revd.TSC

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TINA/Spice: Current Sense Amplifiers for 1mA to 1A