INA220-Q1: bias and offset current

Pol REYMOND

Part Number: INA220-Q1
Other Parts Discussed in Thread: INA226, INA220EVM

Hi team,

In the datasheet, we have only these following details:

« Iin+, Iin- Input bias current at IN+ and IN-« (Ta=25°C, active mode, Vin+ = 12V ; (Vin+ - Vin- ) = 32mV, PGA=/1) typical = 20µA

Could you provide me the Ibias and Ioffset under these conditions:

Ta=85°C
Active mode
Vin+=320mV
Vin- = 0V
PGA= /8
Maximum value

Thanks in advance for your help.

Pol

over 7 years ago

0 Carolus Andrews over 7 years ago

TI__Mastermind 18780 points

Dear Pol,

Unfortunately we can't characterize every condition for the part. Ibias is a typical value on the datasheet, and we do not specify a max value for the part. We also do not spec Ioffset under any condition.

That being said, why are you searching for this information? Is the customer having issues with the input of the device? If you let me know what you are fighting, I'll see what I can do to help.

Carolus

0 Pol REYMOND over 7 years ago in reply to Carolus Andrews

TI__Intellectual 1310 points

Hi Carolus,

The main query is how to estimate the input stage precision on the full range temperature.

We have these values for the INA226. Do you think we could take these to have an estimation ?

Thanks in advance for your help.

Pol

0 Carolus Andrews over 7 years ago in reply to Pol REYMOND

TI__Mastermind 18780 points

Dear Pol,

I ran a quick test here in the lab on the INA220EVM and found a good estimate for input bias current over temperature at PGA=/8 and a 320mV differential is 20uA on each input pin. We did not have any data available for Ioffset. We typically do not characterize this metric on our parts, as it is several orders of magnitude less than the bias current. The 20uA witnessed in the lab was pretty steady over temp (-40C to 85C). However, keep in mind this is only an estimate from a single part, and we can't guarantee the figure. Your customer would need to characterize their own maximum if they need that metric. Hope this helps. Let me know if you need anything else.

Carolus

0 Pol REYMOND over 7 years ago in reply to Carolus Andrews

TI__Intellectual 1310 points

Hi Carolus,

Thanks for this feedback.
I have an additional question about the ADC voltage reference.
Is there an internal voltage reference or the ADC uses the Vs supply?

Regard,

Pol

0 Carolus Andrews over 7 years ago in reply to Pol REYMOND

TI__Mastermind 18780 points

Dear Pol,

the reference of the ADC is internal to the device.

Carolus

0 Pol REYMOND over 7 years ago in reply to Carolus Andrews

TI__Intellectual 1310 points

Hi Carolus,

Could you have the accuracy of this internal reference?

Thanks in advance.

Pol

Amplifiers

Amplifiers forum

INA220-Q1: bias and offset current