An input-tolerant function can be used for level shifting.
When the maximum operating voltage of an IC is higher than the supply voltage (VCC), the input-tolerant function allows a voltage of up to the maximum operating voltage to be applied to an input while the power supply is active or at 0 V. The input-tolerant function allows level shifting from a higher voltage to a lower voltage.
Product selection options:
The 74VHC and 74LCX series can be used for conversion from 5 V to 3 V.
The 74VCX series can be used for conversion from 3 V to 1.2 V.
The following shows an equivalent circuit for a typical CMOS logic IC.