INA281: Output at negative Vsense

Markus Müller

Part Number: INA281
Other Parts Discussed in Thread: TINA-TI

Hello,

I have a question about the behaviour of the INA281 when a negative Vsense is applied.

In the datasheet it is mentioned that the device needs some time to recover since the device is placed in an overload condition but this is no problem in my application.
However, I am wondering if the output voltage of the device stays at 0V (or the lower rail limit) if negative Vsense is applied or if the output voltage is undefined?

Thank you for your answers.

Kind regards,
Markus

over 1 year ago

0 kai klaas69 over 1 year ago

Guru 140200 points

Hi Markus,

like this?

markus_ina281.TSC

I would run a TINA-TI simulation. TINA-TI is free and can be downloaded here:

https://www.ti.com/tool/TINA-TI

Kai

0 Markus Müller over 1 year ago in reply to kai klaas69

Prodigy 30 points

Yes exactly.
Ok so according to the simulation the output stays at 0V.

I wasn't sure if I can trust Tina-TI since this is outside the normal operation and I wasn't sure if this is implemented correctly in the simulation.

+1 kai klaas69 over 1 year ago in reply to Markus Müller

Guru 140200 points

Hi Markus,

yes, the output of INA281 would like to go more negative. But slamming all the way to GND is all it can do

Kai

+1 Carolus Andrews over 1 year ago in reply to kai klaas69

TI__Mastermind 19255 points

Markus,

Kai is correct here. The device regardless of saturation overdrive is bound to the limits of the swing to GND specification in the datasheet:

Even for devices with charge pumps, the swing can be close, but never truly all the way to GND, and certainly not past it. The value you would most likely see on the output in this scenario is ~5mV, but could be up to 20mV from device to device. Keep in mind that saturation is a non-linear behavior, and we cannot say with certainty how long the device will take to recover after a linear input is again supplied to the device. A typical value you can expect is some number of us.

0 Markus Müller over 1 year ago in reply to Carolus Andrews

Prodigy 30 points

Ok got it, thank you both for your help!

Because of the holidays, TI E2E™ design support forum responses will be delayed from Dec. 25 through Jan. 2. Thank you for your patience.

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INA281: Output at negative Vsense