Description
Each device has an active enable G and a direction control input, DIR. When DIR is high, data flows from the A inputs to the B outputs. When DIR is low, data flows from the B inputs to the A outputs. The HD74HC640 transfers inverted data from one bus to other and the HD74HC643 transfers inverted data from the A bus to the B bus and true data from the B bus to the A bus.

Features
• High Speed Operation: tpd = 12 ns typ (CL = 50 pF)
• High Output Current: Fanout of 15 LSTTL Loads
• Wide Operating Voltage: VCC = 2 to 6 V
• Low Input Current: 1 µA max
• Low Quiescent Supply Current: ICC (static) = 4 µA max (Ta = 25°C)