74LS245 is the basic model but uses more current with up to 90mA per unit and 12ns propagation delay - we have 5 so up to 450mA
74HCT245 CMOS version 70mA max and 15ns propagation delay - 300mA for 5 unit. delta 150mA
74AHCT245 FAST CMOS 75mA max and 8.7ns propagation delay -? 375mA delta 75mA from LS?
74ACT245 FAST CMOS 50mAmax and 8ns propagation? delay. - 250mA so 200mA less than LS?
All have same pinout. ACT is best from a current usage versus speed. Any of these will work but HCT is slower than LS in theory . In practice it might not matter at all and will be the same.
Maciej
