The maximum operating frequency of the SN74HCT245PWR is 50 MHz.
Yes, the SN74HCT245PWR is compatible with 5V systems, but it's recommended to use a voltage regulator to ensure a stable 4.5V to 5.5V supply voltage.
The SN74HCT245PWR has a thermal pad on the bottom of the package. Ensure good thermal contact between the thermal pad and a heat sink or a thermal land on the PCB to dissipate heat effectively.
The SN74HCT245PWR can sink or source up to 6 mA per output pin, and up to 32 mA total for all outputs.
No, the SN74HCT245PWR is not compatible with 3.3V systems. It's designed to operate at 4.5V to 5.5V supply voltage.