The recommended operating voltage range for CD54HC240F3A is 2V to 6V, with a typical voltage of 5V.
When the input pins are not in use, they should be tied to a valid logic level (either VCC or GND) to prevent them from floating and causing unwanted switching.
The maximum frequency of operation for CD54HC240F3A is 25 MHz at 5V and 10 MHz at 3.3V.
To prevent damage due to overvoltage, the output pins should not be driven above VCC + 0.5V or below GND - 0.5V. Additionally, the output pins should not be short-circuited to each other or to VCC or GND.
The power consumption of CD54HC240F3A depends on the operating frequency and voltage. At 5V and 25 MHz, the typical power consumption is around 15 mW. At 3.3V and 10 MHz, the typical power consumption is around 6 mW.
CD54HC240F3A datasheet
by Texas Instruments
