The DS1855 dual nonvolatile (NV) digital potentiometer and secure memory consists of one 100-position linear taper potentiometer, one 256-position linear taper potentiometer, 256 bytes of EEPROM memory, and a 2-wire interface. The DS1855, which features a new software write protect, is an upgrade of the DS1845. The DS1855 provides an ideal method for setting bias voltages and currents in control applications using a minimum of circuitry. The EEPROM memory allows a user to store configuration or calibration data for a specific system or device as well as provide control of the potentiometer wiper settings. Any type of user information may reside in the first 248 bytes of this memory. The next two addresses of EEPROM memory are for potentiometer settings and the remaining 6 bytes of memory are reserved. These reserved and potentiometer registers should not be used for data storage. Access to this EEPROM is via an industry-standard 2-wire bus. The interface I/O pins consist of SDA and SCL. The wiper position of the DS1855, as well as EEPROM data, can be write-protected through hardware using the