TPS3898: Variance in VIT+

Kyle Mehringer

Intellectual 1530 points

Part Number: TPS3898

Tool/software:

Hello,

We have a question in regards to the min/max of the Positive-going input threshold voltage (VIT+) in the datasheet.

Min=0.495V

Max=0.505V

What are the reasons for this variance? Is it due to mechanical/packaging variance or is it due to temperature variance? I noticed the 500mV reference internal to the part. Again same question, is the variance temperature related or mechanical related?

Thank you,

Kyle

4 months ago

0 Jesse Villanueva 4 months ago

TI__Mastermind 18780 points

Hi Kyle,

Majority of the variance is due to temperature, min and max values are specd across temperature, but there are also some mechanical and manufacturing variance accounted in the value. One thing to note is that during final test of the device, there are guard bands implemented so typically the device does not come close the min and max value of the datasheet at worst case.

Jesse

0 Kyle Mehringer 4 months ago in reply to Jesse Villanueva

TI__Intellectual 1530 points

Hello Jesse,

Can you give us the exact margin that accounts for temperature? We can't take into account mechanical/manufacturing variance, but we do know the operating temperature of the part, which is in 25-75 deg C ballpark. We want to know this figure so that we can verify if the current resistor ladder used can accommodate the design environment.

Thank you,

Kyle

0 Jesse Villanueva 4 months ago in reply to Kyle Mehringer

TI__Mastermind 18780 points

Hi Kyle,

Below is the datasheet plot for threshold vs temperature.

Jesse

0 Kyle Mehringer 4 months ago in reply to Jesse Villanueva

TI__Intellectual 1530 points

Thanks Jesse,

That plot makes us feel a bit better. One more question for you.

To confirm, do the numbers in this Figure 8 also account for mechanical/manufacturing differences?

Thank you,

Kyle

0 Kyle Mehringer 4 months ago in reply to Kyle Mehringer

TI__Intellectual 1530 points

Hello Jesse,

Do you have any feedback here?

Thank you,

Kyle

0 Jesse Villanueva 4 months ago in reply to Kyle Mehringer

TI__Mastermind 18780 points

Hi Kyle,

Yes, the value accounts for the total accuracy of the device including all the factors.

Jesse

Power management

Power management forum

TPS3898: Variance in VIT+