HD74HCT449
Description
The HD74HCT449 has 4 bus transceivers. The device has direction control inputs with individual. And this control inputs select data transmissible direction. When GBA is high, A outputs are disable, and when GAB is high, B outputs are disable.
Features
- -
- -
- - LSTTL Output Logic Level patibility as well as CMOS Output patibility High Speed Operation: tpd (A to B) = 12.5 ns typ (CL = 50 p F) High Output Current: Fanout of 15 LSTTL Loads Wide Operating Voltage: VCC = 4.5 to 5.5 V Low Input Current: 1 µA max Low Quiescent Supply Current: ICC (static) = 4 µA max (Ta = 25°C)
Function Table
Enable GBA H X L X H H : L : X : High Level Low Level Irrelevant. GAB H L X H X Direction DIR X H L H L Operation Isolation A data to B bus B data to A bus Isolation Isolation
Pin Arrangement
GBA 1 A1 2 DIR2 3 A2 4 A3 5 DIR3 6 A4 7 GND 8 (Top view)
16 VCC 15 GAB 14 B1 13 DIR1 12 B2 11 B3 10 DIR4 9 B4
Logic Diagram
DIR1
A1
B1
To other three transceivers
HD74H...
