[Al Skierkiewicz]

Rickertsen2,
We chose the MAX4172 because it was simple, low parts count, and available from Digikey. We only needed to perform a high current to voltage translation that had a response that was good enough to follow the current pulses that are normal load currents for the input to the speed controllers. Remember that the speed controllers are rapidly turning on and off (varying duty cycle) to simulate variable voltage/current to the motor. The trick was getting a sensor to use for the input. The circuit as you have seen is designed to measure across a known length and width of printed circuit trace.

Matt Krass,
There is a quick trick for soldering flat packages. Use a small iron and tin the pads of the circuit board first. Then it is a simple matter of touching the soldering iron to the lead of the IC long enough to just melt the solder underneath and you are done. Repeat for each lead. Of course there is always the solder paste, reflow method if it's available.