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INA293: Low Vsense condition.

Guru 10385 points
Part Number: INA293

Hi team.

I'd like to know about the low Vsense condition.

The following graph is shown in INA19x's datasheet.



Could you share with us that like this graph for INA293?

Sincerely.
Kengo.

  • Hello Kengo,

    Thankfully, the INA293 does not have this behavior due to an improved input architecture. It shows linear behavior even with Vsense < 20mV. Section 7.3.1.3 of the datasheet mentions this:

    7.3.1.3 Low VSENSE Operation

    The INA293 operates with high performance across the entire valid VSENSE range. The zero-drift input architecture of the INA293 provides the low offset voltage and low offset drift needed to measure low VSENSE levels accurately across the wide operating temperature of –40°C to +125°C. Low VSENSE operation is particularly beneficial when using low ohmic shunts for low current measurements, as power losses across the shunt are significantly reduced."

    Best regards,

    Ian Williams
    Applications Manager
    Current Sensing

  • Hi Ian,

    Thank you for your support.

    I understood about low Vsense operation.

    However, in my customer, the output is the same(4V) between 1A and 4.5A for Isense.
    * Normal value is output at 4.5A or more.

    The following are the settings.

    ・Gain : 100V/V
    ・Schematic : From the data sheet.
      
    ・Rsense=9mΩ
    ・Isense=1A~5.5A
    ・Rin=10Ω
    ・Cin=1000pF

    What kind of problem do you have?
    I had requested a waveform with my customer.

    Sincerely.
    Kengo.

  • Hi Kengo,

    Based on your description, the shunt voltage (IN+ - IN-) will range from 9mV to 49.5mV. 

    Which gain version is being used? Even at the minimum gain of 20V/V, the output should range from 180mV to 990mV.

    Can you please probe the voltage directly at the IN+ and IN- pins to see what is truly being applied to the device? Can you also provide a real schematic for debug?

    Best regards,

    Ian Williams