Five 32-tap devices have been added to Catalyst Semiconductor's family of more than 30 digitally programmable potentiometers (see the Figure). The CAT5123, CAT5124, and CAT5125 are volatile devices, while the CAT5127 and CAT5129 offer nonvolatile wiper storage. All feature a user-friendly up/down control interface. The new digital potentiometers offer low-noise, stable, and reliable alternatives to digital-to-analog converters (DACs) and mechanical pots. The CAT5127 comes in an eight-lead, 2- by 2.5-mm thin dual flat no-lead (TDFN) package or an eight-lead mini small-outline package. The CAT5129 comes in a six-lead SOT23 package. The CAT5123, CAT5124, and CAT5125 also come in SOT23 packages. Resistance values of 10 kΩ, 50 kΩ, and 100 kΩ are available.
The CAT5127 and CAT5129 feature on-chip nonvolatile, EEPROM memory, which permits designers to calibrate once and retain the setting in memory, even if power is lost. The wiper position can be preset to any position on the device and, on power up, the wiper will go to the preset position, which is stored in the EEPROM. The CAT5123, CAT5124, and CAT5125 are volatile devices where in wiper powers on at the mid-scale setting. DAC-based approaches typically require external memory and additional interconnects. The new digital potentiometers cost $0.43 in quantities of 10,000, except for the CAT5127 in the TDFN package, which is $0.53. Samples are available now, with projected lead times of 10 weeks for production quantities.
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