Is there more noise data for 1KΩ DigiPots than the 1KHz spot noise spec in the data sheets? For example, the AD5253 (1K) shows 3 nV/√Hz at 1KHz which makes sense for a pure resistance in the neighborhood of 1KΩ. I am interested in the region of 0.1Hz to 100Hz. Since the devices are not simply resistors but semiconductors, is there 1/f noise? If so, has it been characterized? Any data?
BTW, with such low noise, these devices might be attractive as programmable attenuators for low level signal processing. The noise in multiplying DACs is rather high. IMHO.
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Hi, I am working on this query. Give me sometime to get back to you.
Digipots do not suffer from flicker noise dramatically.. the CMOS switches generates some noise but fall at 1Hz approximately, so at 100Hz thermal noise will be dominant.
Hi, the original questioner wanted to know about frequencies from 0.1 Hz on. Is there any data available on noise voltage density in that range (0.1 to 10 Hz)?
We do not have any data available on the voltage noise density from 0.1-10Hz.
As stated above, there will be noise contributed by the CMOS switches at the wiper position, but that will fall off at 1Hz.
Do note that the thermal noise of sqrt(4kTRB) is the dominant factor in the resistor noise.