The maximum frequency of operation for the CD74HC257E is 25 MHz, but it can vary depending on the operating voltage and load capacitance.
To ensure proper power supply, connect VCC to a stable 2-V to 6-V power source, and GND to a reliable ground connection. Also, decouple the power supply with a 0.1-μF capacitor to reduce noise and ensure stable operation.
The maximum input voltage that the CD74HC257E can handle is 6.5 V, which is the absolute maximum rating. However, it's recommended to keep the input voltage within the recommended operating voltage range of 2 V to 6 V for reliable operation.
Yes, the CD74HC257E can be used in a 3.3-V system. In fact, it's a popular choice for 3.3-V systems due to its wide operating voltage range of 2 V to 6 V.
Unused inputs of the CD74HC257E should be tied to a valid logic level (either VCC or GND) to prevent them from floating and causing unwanted switching or power consumption.