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ADS1248 DAC limitation

Peter Clerico
Intellectual 550 points


Hello,

I am seeking the minimum Voltage Compliance spec for the DACs.  The data sheet shows typical (AVdd-0.7V) and a typical curve.

The design intent is to use muxes to switch the DAC current output to one of 16 channels; there may be as much as 100 ohms switch resistance in the muxes.  Because of this, there will be some voltage drop across the muxes, and there is a concern over when the current sources will begin to drop out, which is why knowing the worst-case minimum voltage compliance will be valuable.

In this design, AVdd is 5V.

Thank you in advance.

  • 0
    TI__Guru 55466 points

    Hello Peter,

    Figure 47 and Figure 48 of the datasheet show a little more detail; the worst case compliance occurs with the 1.5mA setting.  This parameter is not guaranteed in the datasheet; so we can only provide an estimate.  At 1.5mA, ; with 5V analog voltage supply; the compliance is about AVDD-1.5V.  The plots below should be helpful.

    Best Regards,

    Luis