HD74HC640/HD74HC643
Octal Bus Transceivers (with 3-state outputs)
Description
Each device has an active enable G and a ...
HD74HC640/HD74HC643
Octal Bus Transceivers (with 3-state outputs)
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)
Function Table
Control Inputs G L L H DIR L H X Operation HD74HC640 B data to A bus A data to B bus Isolation HD74HC643 B data to A bus A data to B bus Isolation
HD74HC640/HD74HC643
Pin Arrangement
HD74HC640
DIR A1 A2 A3 A4 A5 A6 A7 A8
1 2 3 4 5 6 7 8 9
20 VCC 19 Enable G 18 B1 17 B2 16 B3 15 B4 14 B5 13 B6 12 B7 11 B8
GND 10
(Top View)
2
HD74HC640/HD74HC643
HD74HC643
DIR A1 A2 A3 A4 A5 A6 A7 A8
1 2 3 4 5 6 7 8 9
20 VCC 19 Enable G 18 B1 17 B2 16 B3 15 B4 14 B5 13 B6 12 B7 11 B8
GND 10
(Top View)
Absolute Maximum Ratings
Item Supply
voltage range Input
voltage Output
voltage Output current DC current drain per VCC , GND DC input diode current DC output diode current Power Dissipation per package Storage temperature Symbol VCC VIN VOUT I OUT I CC, I GND I IK I OK PT Tstg Ra...