So I've used a resistor and diode to level-shift from 5v to 3.3v, but that's been for general logic - the fastest thing I've done with that is 9600 bps serial.
I now have a need to feed a 3.3v powered microcontroller (an ATXMega32E5) from a 10 MHz clock signal, which I only presently have available as a 5v square wave (an output from an NB3N551 powered at 5v).
I propose to use a 10 kΩ series resistor followed by a 3.3v zener diode. Circuitlab simulation seems to show this would work, but I am not sure I trust it to be a complete enough simulation.
Is that simple zener clipper likely to work acceptably, or is something more sophisticated called for?