The AD7376 provides a single channel, 128-position digitallycontrolled variable resistor (VR) device. This device performs the same electronic adjustment function as a potentiometer or variable resistor. These products were optimized for instrument and test equipment applications where a combination of high voltage with a choice between bandwidth or power dissipation are available as a result of the wide selection of end-to-end terminal resistance values. The AD7376 contains a fixed resistor with a wiper contact that taps the fixed resistor value at a point determined by a digital code loaded into the SPI-compatible serial-input register. The resistance between the wiper and either endpoint of the fixed resistor varies linearly with respect to the digital code transferred into the VR latch. The 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, 50 k, 100 k or 1 M has a nominal temperature coefficient of 300 ppm/C. The VR has its own VR latch which holds its programmed resistance value. The VR latch is updated from an internal serial-toparallel shift register which is loaded from a standard 3-wire serial-input digital interface. Seven data bits make up the data word clocked into the serial data input register (SDI). Only the last seven bits of the data word loaded are transferred into the 7-bit VR latch when the CS strobe is returned to logic high. A serial data output pin (SDO) at the opposite end of the serial register allows simple daisy-chaining in multiple VR applications without additional external decoding logic. The reset (RS) pin forces the wiper to the midscale position by loading 40H into the VR latch. The SHDN pin forces the resistor *Patent Number: 5495245