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Advantage of LDAC for single-channel DAC?

Can you explain the performance benefits of using the LDAC pin for a single-channel DAC?

I'm particularly interested in minimising output noise and settling time. The datasheet I'm looking at is the AD5542A.

Thanks very much for your help

  • Hi, 

    LDAC benefits more the functionality rather than performance. It allows multiple channels on a device (for multi-channel DACs) or multiple DAC devices (for single-channel DACs) to be controlled synchronously or asynchronously. In terms of output noise, it shouldn't be affected by LDAC. On the settling time, however, having LDAC tied low will reduce the latency from sending the command to the start of the DAC output transitioning to the programmed value. The settling time spec in the datasheet should be characterized in this setup. 

    Best regards,

    Ian

  • Thanks for your reply Ian.

    I now understand the latency from command send will be different with LDAC tied/independent. The output would start transition at different times in each case (controlled by CS or LDAC). This is not a problem, I'm more interested in the time that the DAC output is unsettled.

    I assume that the duration of DAC output transition will be the same in either case? Can you confirm this?

    To clarify - does using/tying the LDAC have any effect on the duration of DAC output transition?

    Thank you!

    Jamie

  • Hi Jamie, 

    The item you're referring to is the slew rate of the output. And No, the LDAC won't affect the slew rate. 

    ~Ian