AD5171 is a 64-bit, one-time programmable (OTP) digital potentiometer2, which uses fusing technology to achieve memory retention of the resistance setting function. OTP is a cost-effective alternative to the EEMEM method for new memory settings where the user does not need to reprogram digital potentiometers. This device performs the same electronic adjustment function as most mechanical scissors and do with variable resistors. The AD5171 is digitally controlled via a 2-wire I2C compatible. It allows unlimited adjustment before permanently setting the resistance value. Upon OTP activation, the final value is determined after a permanent fuse blow command is sent, thus freezing the wiper position at a given setting (similar to mechanically trimming an epoxy). When this permanent setting is achieved, this value will not change with changes in voltage or ambient pressure under normal operating conditions. To verify the success of permanent programming, ADI's patterned OTP verify fuse status can be discerned from the verify bits of the two read modes. For applications, in the factory program AD5171, Analog Devices provides device programming software that works across XP® platforms including Windows NT® Windows® 95. The application of this software effectively replaces the need for an external I2C controller or host processor, thus greatly reducing the user's development time. An evaluation board for the AD5171 is available that includes a factory-programmed application, software for conversion, connectors, and cables. AD5171 is in a compact SOT-23-8 package. All parts are guaranteed over the automotive temperature range of -40°C to +125°C. In addition to its unique OTP function, the AD5171 fits itself well as well as other general-purpose digital potentiometer applications due to its temperature performance, small form factor, and low cost.