Digital Potentiometers Include Variable Resistance Control

Aimed at systems where a variable resistance must be maintained during the manufacturing process, the X9421 and X9429 64-tap, non-volatile digital potentiometers provide four six-bit EEPROM registers per potentiometer. This is said to allow the user to save resistance values during power down and to pre-set resistor values.
Both devices operate on a single 2.7V supply and have four nonvolatile registers that can be individually programmed. Equally, they can recover the last position after a power-down cycle. They differ in that the X9429 communicates via a two-wire interface serial port and the X9421 uses an SPI interface serial port. Both devices are available now in sample and production quantities.