The maximum frequency of operation for the SN74HCT245NSR is 50 MHz.
Yes, the SN74HCT245NSR 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 SN74HCT245NSR has a thermal pad on the bottom of the package, which should be connected to a heat sink or a thermal pad on the PCB to ensure proper heat dissipation.
The SN74HCT245NSR is rated for operation from -40°C to 125°C, but it's recommended to derate the device's performance at high temperatures to ensure reliability.
To ensure signal integrity, use a low-impedance PCB design, keep signal traces short, and use termination resistors as needed to minimize signal reflections.