I have been doing some reading about the AD5171 (i2c 6bit digital pot) chips, and in the datasheet it states the following (http://datasheet.octopart.com/AD5171BRJZ10-R2-Analog-Devices-datasheet-8546.pdf) page 20:
RESOLUTION ENHANCEMENT The resolution can be doubled in the potentiometer mode of operation by using three digital potentiometers. Borrowed from ADI's patented RDAC segmentation technique, users can con-figure three AD5171s (Figure 46) to double the resolution. First, U3 must be parallel with a discrete resistor, RP, which is chosen to be equal to a step resistance (RP = RAB/64). Adjusting U1 and U2 together forms the coarse 6-bit adjustment, and adjusting U3 alone forms the finer 6-bit adjustment. As a result, the effective resolution becomes 12-bit.
That sounds great, but the chips are only available in small SMT packages, and I really want to prototype with DIP. There are various SPI chips in DIP format that are cheap, and I was wondering if anyone sees anything wrong with putting 3 of these as described in the AD5171 description, in order to get a higher resolution?