I'm designing a circuit (24 dB/octave Linkwitz/Riley audio crossover) that calls for 16 adjustable resistors and they have to match within 1% of each other, or maybe 2%.
I'm upgrading a piece of equipment which already has I2c with spare plugs on the bus present, so I'm thinking I2c chips. One that I have in mind, is the Intersil ISL23345. It's a quad I2c variable resistor chip.
However, even though channel-to-channel tolerance is 1%, global tolerance is 20% or 30%, which is way too much for me.
This tolerance figure seems to be the norm for all brands of digital VR's (Analog Devices, Microchip, Intersil,...).
So, what are my options here? How can I set the value for 16 resistors to within 1% tolerance?