Dual 32-tap log pot with mute and zero-cross — what it does
The Maxim Integrated MAX5408ETE+ is a dual-channel, 32-tap digital potentiometer with a logarithmic taper, packaged in a 16-TQFN (4x4 mm). Each of the two potentiometer circuits presents a 10kΩ end-to-end resistance with a wiper resistance of 1000 Ω typical. Communication is over an SPI interface, and the wiper position is volatile — it resets to midscale on power-up. The operating supply range is 2.7 V to 3.6 V, and the part is rated over the industrial temperature range of -40°C to +85°C.
Mute and zero-cross sense — the audio-specific features
The part includes a mute function and a zero-cross sense feature. The zero-cross sense synchronises wiper transitions to the AC zero-crossing of the audio signal, which suppresses the audible pop and click that otherwise occurs when the wiper moves to a new tap.
32 taps and ±30% tolerance — resolution and absolute accuracy
With 32 taps, the wiper can be set to 32 discrete positions between ground and the reference voltage. The ±30% tolerance on the absolute resistance (10 kΩ) is typical for digital potentiometers.