laglead said:
I think there are two reasons:
1. Parasitic PNP characteristc change.
2. PTAT current change due to resistor value change. This will lead to little change in Vbe.
This brought me another question about BGR. It's said that the size of diode to form Vbe in Vbgr can be arbitary. But with same current, different size of diode will generate different Vbe, and this adds up with PTAT current across resistor, the final Vbgr will be generated slightly different. Is this correct? Or I missed some points.
Thanks,