Seekat Benchmarks
Noise:
Below we compare the voltage noise on the output of OpenDAC Seekat with several other widely used laboratory DACs, including the Harvard BabyDAC, Keithley 2400, SR830 lock-in amplifier auxiliary output, and a future low-noise OpenDAC release based on the Analog Devices AD5780 chip. These measurements are consistent with the AD5764 datasheet. We also tested a National Instruments PCI-6259 card (not shown), which showed dozens of spikes below 100 Hz in the 2-3 µV/√Hz range. All of these measurements were obtained at zero output voltage; at full scale the noise increases in all cases by about a factor of 10. For comparison of noise performance above 1 kHz, we note that the Harvard BabyDAC has a filter capacitor on the output op amp, whereas openDACs are BYOF (build your own filters).
Nonlinearity:
We measured the integral and differential nonlinearity for each of the 2^16 codes of one channel of a Seekat, which also agrees with the AD5764 datasheet.