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DAC8814EVM: Stability of voltages

Jesús Maza Muñoz
Prodigy 30 points
Part Number: DAC8814EVM
Other Parts Discussed in Thread: DAC8562T, DAC8814, DAC81416,

I know that these three, if I am not wrong, can operate between -10 V and +10 V. But are they stable? I mean, what is the error that I can expect once I establish that voltage ?

  • 0
    TI__Mastermind 32768 points

    Hi Jesus, 

    I am going to consolidate your posts to one thread. 

    The DAC8562T does not have a ±10V range. The DAC81416 and DAC8814 do both have a ±10V range.

    The DAC8814 is an MDAC which means it requires an output buffer. For a bipolar output you'd need to use the following configuration:

    The only change in the output for the DAC8814 and DAC81416 once you set the output voltage will be due to any drift in the gain error, offset error, or reference voltage.

    The DAC81416 has an internal reference, so the drift spec is shown in the datasheet along with the gain and offset error specs. The DAC8814 requires an external reference, so the drift will be dependent on the drift of the reference you choose. Similarly, any drift specs of the external output buffer you use will affect the voltage drift.

    Best,

    Katlynne 

  • 0 in reply to Katlynne Jones
    Prodigy 30 points

    Hi Katlynne,

    Thank you for your answer. Regarding the DAC8814, you showed me the “output buffer” that is needed. However, I asked about the DAC8814EVM. Isn’t the “Output buffer circuit” already integrated in it?

    Also, I would like to ask you these questions:

    • Is it controlled by the SPI interface?
    • Is the Vref ±10 V or ±12 V?
    • Does it also need a +5V supply?
    • Does that device use the DAC8814C or DAC8814B? I’m asking this because one of them has a ±1 LSB accuracy and the other has ±4 LSB accuracy
  • +1 in reply to Jesús Maza Muñoz
    TI__Mastermind 32768 points

    Hi Jesus, 

    Yes you're right. The output buffer is included on the EVM

    Yes, the EVM uses SPI to communicate with the DAC.

    VREF is +10V, but the required VCC for the EVM is ±12V. 

    The EVM has an onboard reference that generates the +10V off of the ±12V VCC which allows for a ±10V output from the output buffer. 

    The EVM uses the DAC8814ICDB (C version). If you want to evaluate the B version of the DAC8814, you could order the B version separately and populate it on the EVM. 

    Best,

    Katlynne Jones