I'm using an AD5206-B10 digital potentiometer chip to tie into the joystick port of an electric wheelchair using an Arduino Uno. I'm powering the SPI portion of the chip from the Arduino, but I'm powering three pot circuits using power from the joystick port in the wheelchair controller. Both grounds are tied together. Unfortunately I'm finding that the AD5206 is heating up after some time. When it gets hot it eventually stops responding to SPI commands.
I'm a bit of an electronics noob so if anyone has a suggestion it would be appreciated. The voltage from the Joystick port is 5v and looks pretty steady when measured with a multimeter. My first thought was that I might be somehow pulling way too much current from the port but when measured it looks like it peaks at about 2.05 ma. Both voltage and current seem like they should be well within the normal operating specs of the chip. Does anyone know if it is normal for these chips to heat up? Is there something else I should be looking at in terms of a bad circuit? Right now this is just breadboarded.