256-tap digital potentiometer

2 September 2009 Analogue, Mixed Signal, LSI

ON Semiconductor has added a new 256-tap, single-channel linear-taper device to its family of digitally programmable potentiometers (DPP). The CAT5140 is a low-noise alternative to DACs and mechanical potentiometers, and it features an on-chip, 8-bit, non-volatile EEPROM memory, which allows designers to calibrate once and retain the wiper setting in memory on power-up. The new DPP also provides five additional non-volatile registers for general-purpose data storage, as well as a volatile wiper register for applications requiring temporary storage.

The integrated memory options in the CAT5140 save board space and costs compared to DAC-based design approaches, which typically require external memory and additional interconnects. Additionally, the ultra-low standby current of 2 μA, combined with integrated memory, make it well suited for mechanical potentiometer replacement in space-constrained, handheld applications. Since it is digitally programmable, the device is insensitive to mechanical vibrations, shock and oxidation, making it more stable and ­reliable than mechanical potentiometers across most environmental conditions.

The CAT5140 is a single-channel, linear-taper digital potentiometer with a 400 kHz, I²C-compatible interface for LCD screen adjustment; automated calibration; contrast, brightness and volume control; gain adjustment and line impedance matching applications. EEPROM endurance is 2 million data write stores and data retention is 100 years. The device operates from a 2,5 to 5,5 V supply voltage and comes in resistance values of 50 and 100 kΩ.

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