AD5272_wiper resistance

Question As specified in the section of SPECIFICATIONS in its datasheet, the wiper resistance when code is zero scale should be 35ohm (typical) and 70ohm (max). Refer to figure1 in the attachment However, it is said in page 23 of the datasheet that in the zero-scale condition, a finite total wiper resistance of 120 Ω is present. It seems to be a contradiction? Answer If you see figure 46, you can see that there are a few switches in the signal path. Traditionally, the wiper resistance is mainly the last switch resistance. That’s why the resistance at zero scale is different than specified. The other two switches in the path are already computed for the final LSB value, so the only exception is zero scale code, where the switches cannot be hidden. You can find more info in this article, http://www.analog.com/library/analogDialogue/archives/45-08/digipot.html