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DAC108S085: Output Error Occurs

user6265997
Prodigy 20 points
Part Number: DAC108S085

Hi,

I have a question about the error of the output value.

1) What is the LSB of the DAC output error if I keep sending the same value?  I want to know the repetition error.

2) Also, if the same value is continuously transmitted, the DAC output value fluctuates by about 4 LSB in a specific temperature range (around 30 ° C around the IC). I want to know the solution about this problem.

3) Are there any DAC108S085CIMT compatible products with smaller errors?

  • 0
    TI__Mastermind 46290 points

    Hello,

    There should not be any reason for variation when the DAC is written with the same code repeatedly as nothing about the resistor string or interpolating amplifier at the output changes from one write to the next. 4 LSBs is a pretty significant amount of change which would suggest to me that you are either seeing effects of digital feed-through or other noise sources in your system.

    If you are constantly writing to the DAC and constantly making measurements the sharp edges of the digital signals can AC couple themselves into the output through board and device-level parasitics. This shouldn't necessarily have a strong relationship with temperature, though, so I would expect you see something like this across all temperatures. Digital feedthrough, PSRR, and other AC coupling parameters which I would associated with this observation typically do not change much with temperature.

    There aren't any devices directly pin to pin with this DAC, but there are other similar options as it concerns 8-channel, medium resolution, SPI interfaced DACs. At the moment, though, I am not sure the issue is really associated with this device.

    Perhaps you could share some oscilloscope captures of the output deviations to help us better understand exactly what is happening?

  • 0 in reply to Kevin Duke
    Prodigy 20 points

    Hi Kevin,

    Thank you for your quick reply. I understand the DAC does not fluctuate basically in my situation.

    I think problem is in our system not be in DAC-IC. So I'll check the microcomputer and peripheral circuit transmit data to DAC-IC and also firmware.

    If problem won't solve, I capture transmitting data by oscilloscope and share you the captures. Please help me again in that case.

  • 0 in reply to user6265997
    TI__Mastermind 46290 points

    Hi,

    That sounds good to me. For now I will mark this thread as closed. If it goes inactive for 2 weeks it will automatically be locked, but you may click "Ask a Related Question" or start a new thread and either someone from my team or I will continue to support you.