We can see temperature drift data on AD9139 datasheet Rev.0, as Gain Drift = 100ppm/degC, and Reference Voltage Drift = 30 ppm/degC. When we use external reference, does it mean total voltage gain drift must becomes to 100+30=130 ppm/degC, doesn't it ?
When ADI use word "temperature drift" as decribed in ppm, it doesn't matter to its direction( plus or minus ), so 100 ppm/degC and 30 ppm/degC can be -100 or -30, thus gain drift when using external reference can be from +130ppm/degC to -130ppm/degC, we're assuming, but is it correct ?
Or accumulated gain drift 130 ppm/degC is full range so, it can be from -65ppm/degC to 65 ppm/degC as center on drift=0, isn't it ?
Sorry to ask these basics, but your confirmations are very much appreciated.