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INA241A: Can we use this part in a converter with switching freq of 500kHz?

Nitin Kumar
Prodigy 10 points
Part Number: INA241A

Tool/software:

Hi,

We are making a dc-dc boost (5V in to 24V out) converter whose switching frequency is 500KHz. According to datasheet of INA241A it can support freq. only up to 125kHz but its signal BW is 1.1MHz . Can we use INA241A as current sense amplifier for this converter?

  • 0
    TI__Mastermind 22385 points

    Nitin, 

    The reason we list frequency support of up to 125kHz is due to the PWM rejection feature of the part, as well as the need to capture a decent number of harmonics in the signal to recreate the waveform.

    Dependent on whether you are looking to measure average current or peak to peak current, the PWM rejection on the peak mode side could result in unwanted changes to the waveform at the 500kHz speed. If you wanted to explore full BW options, I would recommend looking at the INA296, which is the same part without the PWM rejection features. You could simulate this with the available models on ti.com to have a look at the parts response to your measurement scheme and see if this would be sufficient for the application. However, note that even with the 1.1Mhz BW, again dependent on the waveshape and the associated harmonics beyond 500kHz, you could potentially see distortion here due to the harmonic attenuation outside of 1.1MHz.