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DAC8771EVM: Use the DAC8771 as 1KHz AWG?

Steven Weigand
Prodigy 10 points
Part Number: DAC8771EVM
Other Parts Discussed in Thread: DAC8771, DAC8760, DAC63202

Hi,

Is it possible to use the DAC8771EVM as a 1KHz arbitrary waveform generator? The datasheet does not specify maximum sample rate. Thus, I presume it is only meant for static operation.
But I am looking for a DAC that support negative to positive outputs (approx +/-5V output). The DAC8771 fulfills the pos/neg output voltage well. But can it be used to generate arbitrary waveforms?
The SPI-Interface makes this a little difficult because it has write overhead. And driving it with a real-time OS computer (Raspberry Pi) does not make it easy to control an equal spaced sampling rate.

My main questions:

1. Is it possible to use the DAC8771EVM for the above mentioned application? (1KHz AWG +/-5V)

2. If there is another part that is more suited for this application, could you please suggest one?

Thanks,
Steven

  • 0
    TI__Guru* 94725 points

    Steven,


    Yes, you should be able to use the DAC8771 as a 1kHz sine wave generator. Instead of thinking of the sample rate, we specify the settling time of the DAC (which for this device is in the 10 to 15us range). This device and the DAC8760 both are able to output a bipolar output voltage to generate a sine wave.

    Depending on your application requirements, you may opt for something a bit simpler. The DAC63202 is a 12-bit device (two-channel) which we call a smart DAC. In the device, there is user-programmable nonvolatile memory that can be used to set some pre-programmed DAC outputs. In the datasheet on page 40, we list a set of values that can be used to generate a 24-point sine waveform. Once programmed, this would run automatically without needing to set the DAC codes from the microcontroller. This device runs on 0-5V, and to get bipolar outputs, you would need to add some extra circuitry.

    I haven't used one of these devices myself, but I think this could work for you. Again, it depends on what you need.


    Joseph Wu