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INA293-Q1: Current Sense Amplifier Rise Time, Prop Delay, and Response Time Data

Chase Richard
Prodigy 10 points
Part Number: INA293-Q1
Other Parts Discussed in Thread: INA293, INA240, INA281, INA290

Do the INA240, INA281, INA290, and INA293 have rise time, propagation delay, and response time data? I only see settling time on the datasheet.  I'm looking to compare these sensors with allegro sensors which provide the previously 3 mentioned times.

  • 0
    TI__Mastermind 26485 points

    Hello Chase,

    Most of the time you can get the propagation delay from our step response.  Some plots do not have the resolution you may be looking for.  As for rise time you should go off the slew rate as this will be your limiting factor for the rise time.  A good estimate can be done with our models.  

    Be aware that the INA293, INA281, and INA290 use an internal current feedback that will cause the bandwidth change with the input voltage level.  So this could change your response time.

  • 0 in reply to Javier Contreras4
    Prodigy 10 points

    Is it possible to get a higher resolution (time on x-axis) of the step response for the listed sensors above?

  • 0 in reply to Chase Richard
    TI__Mastermind 26485 points

    Chase,

    I do not have any I have some EVMs that I could check quickly but it would be a rough number and will not have any statistical value.  It would be best if you can provide conditions so that it is more in line of what you are looking for.  Also you can quickly evaluate this to more closely match your conditions.  For the ones I mentioned the worst case is when you start at 0V Vsense and go to the value you expect.  If you start with Vsense <0V there is a recovery time you will deal with.

  • 0 in reply to Javier Contreras4
    Prodigy 10 points

    Javier,

    Estimated times would be nice understanding that it's not statistically accurate.  Ultimately, I'm looking to use these sensors in a control system that is rapidly changing (us range) so these high BW sensors are expected to perform well.  It would be nice to know rise time for worst-case scenarios (0V Vsense to Vfinal where Vfinal is a 1V+ step). Vsense will never be < 0V in my application(s).  Just so we're on the same page: Trise = time it takes from 10% to 90% of final value, Prop delay = time between 20% of final input signal to 20% of final output signal, and response time = time between applied current reaches 80% of final value and when sensor reaches 80% of its output corresponding to applied current.

  • 0 in reply to Chase Richard
    TI__Mastermind 26485 points

    Chase,

    Just so you are aware I will most likely do this on the bench with voltage which is the same, and I will use the gain of 20 versions.

  • 0 in reply to Javier Contreras4
    Prodigy 10 points

    I private messaged you to provide some further info.

  • 0 in reply to Chase Richard
    TI__Mastermind 26485 points

    Hello Chase,

    I have some data for you.  I will share some screen shots.  I just realized that I got up to 80% for all delays.  I did not zoom into the input signal as it is pretty fast.  I will share that since the INA293 and INA290 and INA281 are current feedback and have lower bandwidth like I mentioned.  If you input starts at a higher Vsense input it will respond quicker.  Also with the Vsense voltage being negative will cause a larger delay due to the device getting out of saturation.

    Conditions:  Using EVM with no capacitive load except for Oscilloscope with 1x probe.  I only placed a couple screenshots.  I would suggest getting an EVM and attempting for you specific load and conditions if you need more data.

    Vs= 5V

    VCM = 12V 

    INA240 VREF = 2.5V

    Step Input from 0V-1V/Gain unless noted.   *Scope shot below:  Yellow is AC coupled input.  Green is Output.

    Device Delay to 20% Delay to 80%
    INA240A1 580ns 1.3µs
    INA240A2 * 560ns 1.1µs
    INA290A1  500ns 860ns

    INA290A2*

    326ns

    		 770ns
    INA290A2 with output step from 2V-3V* 220ns 560ns
    INA293A1 288ns 594ns
    INA293A2* 280ns 610ns
    INA293 with output step from 3V-4V* 154ns 480ns

    INA240A2 Input step and time to get to 80% = 800mV

    INA290A2 input step with time from input step to 20%= 200mV

    Input INA290A2 step with output from 2V to 3V at output delay to 20%= 2.2V  

    INA293A2 80%

    INA293 from 3V to4V step 80%