• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 47 subscribers
  • Views 97 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

INA240-Q1: INA240A1-Q

Giridhar N
Prodigy 180 points
Part Number: INA240-Q1

Tool/software:

Hi Team,

I am using INA240A1-Q IC in one of my project. 

I am planning to do Current Sense Amplifier output error calculation. So, i need below information:

1. What are the  min. and max. values of input bias current?? In datasheet mention 90 uA (typical current).

2. What are the Ib+ , Ib-  values??  Are the both values need to consider 90uA or other ??

3. What is the output voltage eq of INA240A1??

Is below equation correct??

CSA out = (Vref2- Vref1)/2  + [Vsense ± Voffset *( 1± Temp. drift. tol) + Ibias* Rin ]* Gain *( 1 ± Total gain error) * (1 ± Non- linearity error)

Where :

Vsense = sense voltage across shunt resistor

Voffset = offset voltage;

Rin = CSA input resistor 

Thanks & Regards,

Giridhar.

  • 0
    TI__Mastermind 31760 points

    Hi Giridhar,

    In the Electrical table, Ib (positive or negative input pin) is specified with the condition of Vsense=0mV and Vcm=12V. Under this condition, you can use ±10% as min/max in your calculation.

    Ib varies with both Vsense and Vcm however, as show by these curves in the datasheet:

       

    The ideal output equation is:

    CSA out = Vref  + Vsense * Gain, where Vref is the effective reference voltage determined by the configuration of REF1/2 pins. For details on Vref configuration, please refer to section “8.4 Device Functional Modes”.

    To take into account of total error, the typical process is to calculate total error and then combine with ideal output.

    For error calculation, you could refer to section “8.4.4 Calculating Total Error”. To facilitate this effort, there is a calculator tool you’re welcome to take advantage of. You can find it at this link.

    You can also view the training videos, there are some dedicated to error sources and error calculation.

    Guang