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DAC1282: DC Output Generation

Eric Leveille
Prodigy 50 points

Part Number: DAC1282
Other Parts Discussed in Thread: DAC9881, ADS1282,

I'm planning to use this part to generate DC voltages and low-frequency sine waves to test an analog ASIC design, but I'm confused by the datasheet's description of how to generate DC voltages.  I'd like to be able to generate any 24-bit differential DC voltage between -VREF/2 to VREF/2, but section 8.2.2.2 (Table 5 in particular) is only listing 5 options for DC output voltage levels.  Can you please clarify?  

  • 0
    TI__Mastermind 44780 points

    Hi Eric,

    You can calculate the DC voltage based on the equation: Vdc = (Vref / 2) * (DCG[23:0] / 0x7FFFFF) * (Analog Gain)

    The DCG[23:0] register value is a signed 24-bit number, so the ratio of "DCG[23:0] / 0x7FFFFF" results in a value between -1 and +1. Does that help?

    Please note the DAC1282 is a very specialized DAC that is typically used as a test signal to the ADS1282. I mention this because the DAC1282's output is fairly noisy and when it is not used in combination with the ADS1282 and the ADS1282's digital filter (to remove this noise), the performance may be sub-optimal. If you are looking for a high-resolution precision DAC then the DAC9881 might be a better option.

    Best regards,
    Chris