Cirrus Logic AN Integrating CobraNet into Audio Products - Manual (Page 15)

FAQ P RELIMINARY
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CS18101 (CM-2) AppNote1 - rev 1.1 Jan, 2004
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Q: Should I use 3.3v or 5v logic when interfacing to the CM-2 (or CM-1)?
A: The CM-1 and CM-2 interface with 3.3v logic levels, but all the inputs are 5v tolerant.
That being said, every effort should be made to phase out 5v circuits. Today the only
major reason to use 5 volts is when interfacing to some audio converters, but all other
logic is available at 3.3 volts. By using 3.3 volts you lower power consumption, lower
EMI, and can use higher-speed logic. Additionally, future CobraNet modules might
not be +5v tolerant on the inputs.
Q: Why blue PCBs?
A: Green is so overdone. We have gotten tired of green. Red is certainly different but a
little too racy for our conservative engineers. Blue is elegant, soothing, and quite
attractive!