Hi Okui-san,
[quote user="Atsushi Okui"]1) When referring page 3, the term "Zero-scale error" is defined. Please let us clarify the difference between this and Offset error.[/quote]
Please refer to: DAC Essentials: Static specifications & linearity if you need a different explanation please let me know.
[quote user="Atsushi Okui"]2) When using this device, we will need to use 1 external reference to have alignment on all 4 output channels. However, we assume that there are additional concerning on error variation per each channel. If we should take care of this situation, could this device not be the suit solution?[/quote]
The channels are not able to be well matched without software calibration, which is not a trivial approach. This will be the same for other devices as well.
Software calibration, involves measuring the performance of each channel and then creating an equation that will compensate for the offset and gain errors of each channel.
(Code)*(Gain Calibration) + (Offset Calibration) = (Calibrated Code)
The calibrated code is the value that is written to the DAC. The DAC will lose some end-point codes due to the calibration. The calibration is usually done by the MCU communicating to the DAC, but you can also take a look at the DAC7716 which will store and apply the calibration values after you measure them.
If this is something you may be interested in, I can give you some more details in this approach.