A question on the voltage level at the circled node

[lucky6969b]

Consider the voltage level at the circled node,
if that voltage level is calculated by the
Kirchhoffs voltage law (summing from the 5V rail to the 0V rail)
, but if the node is also connected to the chip, we don't know
what components are available inside that chip, can we assume
the voltage level not be affected by the components inside the chip? We can safely calculate the voltage level by just considering the components outside the chip?
Thanks
Jack

 

[chuckey]

The chip may be feeding a reference voltage OUT. I would guess that the junction of R1/R2 would be +2.5V, this would allow the A/D, to read +- 2.5V and not just 0-5V
Frank

 

[FvM]

Right, the circuit is dicussed in the ZN448 datasheet under "Bipolar Operation".