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TMS320F28034: INL (Integral nonlinearity) at ADC for same device

Hisao Uchikoshi
Genius 15300 points

Part Number: TMS320F28034

Hello Experts,

F28034 ADC INL spec is defined as +- 4LSB. We are expecting within the same device INL should be more accurate.

Could you please provide such kind of data? This is used for reference only.

Regards,

Uchikoshi 

  • 0
    TI__Guru 62975 points

    Uchikoshi-san,

    The INL error comes from a combination of random errors from manufacturing tolerance of multiple structures within a single device.  The characteristics of these structures are very similar to each other within a device, but there is still enough variation to produce +/- 4 LSB of INL error.

    -Tommy

  • 0 in reply to tlee
    TI__Genius 15300 points
    Hi Tommy,
    What is the factor to generate this variation? temperature, noise, etc?
    Regards,
    Uchikoshi
  • 0 in reply to Hisao Uchikoshi
    TI__Guru 62975 points
    Uchikoshi-san,

    The variations are due to manufacturing tolerance. For example, if you purchase 50 resistors of 1kΩ ideal resistance, there will be small differences in actual resistance between the resistors.

    There are similar variations for all components on the die (ex: resistors, capacitors, transistors, metal routing, etc). It's the mismatch in electrical characteristics that contribute to INL error.

    -Tommy
  • 0 in reply to tlee
    TI__Genius 15300 points

    Hi Tommy,

    INL is defined for all temperature range. If INL variations are due to manufacturing tolerance, how does temperature variation affect? Can we think temperature variation does not affect INL variation?

    Regards,

    Uchikoshi

  • 0 in reply to Hisao Uchikoshi
    TI__Guru 62975 points
    Uchikoshi-san,

    We have no guidance with respect to how INL might drift across temperature. I would expect this to vary from device to device because the errors are generated by random variations which may or may not drift with temperature.

    -Tommy