PART FINDER FRIDAY – I/O Expanders and MUXes. If you need MORE analog inputs to your micro, you can’t really go wrong with the classics, the 4066 (8:1) and 4067 (16:1). For $1 you can multiplex 16 new channels into one A/D input! The 74′ series versions can run on 2-6V and have ~60 ohms of resistance in the internal FET switch. They are a little noisy but if you are using a microcontroller just let the mux settle for a few milliseconds and toss the first reading and you should be golden!