Electronic Design

First low-voltage digitally controlled potentiometer with < 1% typical resistor tolerance

Essex, England: Intersil claims it’s developed the first low-voltage digitally controlled potentiometer (DCP) with < 1% typical resistor tolerance. Thanks to the ISL22317’s extremely low tolerance, it can be used as a true variable resistor, enabling users to set standard and non-standard resistor values for open-loop applications.

The ISL22317 targets designs that require specific current and resistor values, such as test and measurement circuits, medical devices, backlight controls, or adjusting specific resistances in analog circuits. The patent-pending architecture of the DCP allows it to track an external resistor within 10ppm/°C, improving overall system accuracy for temperatures up to 125°C.

The device reduces programming time and development costs by letting users select accurate predetermined resistor values, as well as use calculated resistor values in schematics. In addition, a designer can apply the known value of one system to calibrate other systems. The device employs an easy-touse I2C interface to program accurate resistor settings greater than 1 million times in the integrated EEPROM memory. It also features a zero-compensated wiper resistance in rheostat mode. Negating wiper resistance improves overall accuracy, especially at the low tap positions where the ratio of wiper resistance to actual resistance is much higher.

With this feature, users are able to do schematic calculations based on an actual 1% value. Competitive solution typically have greater than ±20 percent tolerance of the resistor string in addition to wiper resistance error.

TAGS: Intersil
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