Low-power X-tal driver with enable and internal resistor

The 74AUP1Z04 is a crystal driver with enable and internal resistor. When not in use the EN input can be driven HIGH, putting the device in a low power disable mode with X1 pulled HIGH via RPU, X2 set LOW and Y set HIGH. Schmitt trigger action on the EN input makes the circuit tolerant to slower input rise and fall times across the entire VCC range from 0.8 V to 3.6 V.