Input voltage range for lm336z-5.0?
The term "input voltage" is actually not exactly applied here, since LM336 is a shunt regulator. You can see it roughly as a zener diode.

Check also Figure 11 in the datasheet.



As long as you provide a bias current to it that is at least 0.6mA and at most 10mA (15mA absolute maximum) then the voltage across the regulator/diode will be around 5V.

So, the value of the supply voltage is not important in this application, as long as it is of course higher than the reference voltage.