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DAC122S085: Do we have EVM & noise performance ?

Yuxi Liu(Tony)
Intellectual 2200 points
Part Number: DAC122S085
Other Parts Discussed in Thread: DAC7811, DAC63002

Tool/software:

Hi TIer

Do we have DAC122S085 EVM available?

Customer want to evaluate this chip for noise performance.

Application is Medical - Ultrasound image - TGC circuit.

Could you give some comment on noise comparison between DAC122S085 and DAC7811.

Thank you very much.

  • 0
    TI__Mastermind 32648 points

    Hi Tony, 

    For new designs we would recommend the DAC63002 over the DAC122S085.

    But to answer your questions:

    We have an EVM for the 4 channel version of this device: https://www.ti.com/tool/DAC124S085EVM

    The 4 channel version should be fine for the noise measurement, but the devices are p2p, so you could also swap out the part on the EVM for the DAC122S085.

    The noise from the DAC itself is only due to the thermal noise of the resistor ladders and the output amplifier. These are both pretty minor, so the VREF noise will dominate. I do not have spec for the output amplifier noise, but the thermal noise can be calculated based on the ~60kΩ resistor ladder resistance.

    The DAC7811 is an MDAC, and it's noise will also be dominated by the VREF. The output buffer on this part is external, so the noise contribution there is going to depend on the characteristics of the external device. And similarly, there is the thermal noise from two 10kΩ resistors (the equivalent ladder resistance, and RFB resistance). 

    Best,

    Katlynne Jones