1. If BUF pin is left unconnected, it default 1 or 0? or the pin must be connected to hi or low?
2. Is the transfer function equation (figure 4) in datasheet the same for BUF=1 and BUF=0?
3. I use internal 2.5V reference. If the REFIN/OUT pin connected for testing and calibration, should I add a capacitor (0.1uF) on REFIN/OUT pin and GND pin for avoid reference voltage variation?