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I'm looking over the schematics and PCB layout of the Adafruit TCA9548A I2C Multiplexer breakout board. I've attached the schematic below.

I cannot figure out why there are 10k resistors on the A2,A1,A0 addressing lines. Do these serve just as current-limiting resistors?

enter image description here

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They are just simple pull-down resistors, used to set the default value of the device address.

You can buy multiple of these boards, hook them up to the same bus and give them different addresses by pulling the lines high (note the solder pads on back side of the board).

10K value is a standard pull-up/pull-down resistor value, but anything between 5K and 100K would work just as well.

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  • \$\begingroup\$ Thank you Armandas. That makes sense I was under the impression that the address lines were used to select the channel on the multiplexer and not assign an address to the mux device itself. \$\endgroup\$ Jan 24, 2016 at 18:59

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