The maximum clock frequency of the SN74LS640DWR is 30 MHz.
The SN74LS640DWR requires a single 5V power supply, and it's recommended to use a decoupling capacitor of 0.1uF to 1uF between VCC and GND to ensure proper power supply decoupling.
The SN74LS640DWR can sink or source up to 24mA of current per output pin.
The SN74LS640DWR has a maximum junction temperature of 150°C. Ensure good airflow and consider using a heat sink if the device is expected to operate at high temperatures or high frequencies.
Use a low-inductance layout and routing to minimize signal reflections and noise. Keep the clock signal traces short and away from other signals, and use a ground plane to reduce electromagnetic interference.