The AD5200 and AD5201 are programmable resistor devices, with 256 positions and 33 positions respectively, that can be digitally controlled through a 3-wire SPI serial interface. The terms programmable resistor, variable resistor (VR), and RDAC are commonly used interchangeably to refer to digital potentiometers. These devices perform the same electronic adjustment function as a potentiometer or variable resistor. Both AD5200/AD5201 contain a single variable resistor in the compact SOIC-10 package. Each device contains a fixed wiper resistance at the wiper contact that taps the programmable resistance at a point determined by a digital code. The code is loaded in the serial input register. The resistance between the wiper and either end point of the programmable resistor varies linearly with respect to the digital code transferred into the VR latch. Each variable resistor offers a completely programmable value of resistance, between the A terminal and the wiper, or the B terminal and the wiper. The fixed A-to-B terminal resistance of 10 k or 50 k