74F640 Datasheet, PDF (2/6 Pages) NXP Semiconductors – Octal bus transceiver, inverting 3-State

Unit Loading/Fan Out
Pin Names
OE
T/R
A₀–A₇
B₀–B₇
Description
Output Enable Input (Active LOW)
Transmit/Receive Input
Side A Inputs or
3-STATE Outputs
Side B Inputs or
3-STATE Outputs
U.L.
HIGH/LOW
1.0/1.0
1.0/1.0
3.5/0.667
600/106.6
3.5/0.667
600/106.6
Input I_IH/I_IL
Output I_OH/I_OL
20 µA/−0.6 mA
20 µA/−0.6 mA
70 µA/−0.4 mA
−12 mA/64 mA
70 µA/−0.4 mA
−12 mA/64 mA
Functional Description
The output enable (OE) is active LOW. If the device is dis-
abled (OE HIGH), the outputs are in the high impedance
state. The transmit/receive input (T/R) controls whether
data is transmitted from the A bus to the B bus or from the
B bus to the A bus. When T/R is LOW, B data is sent to the
A bus. If T/R is HIGH, A data is sent to the B bus.
Logic Diagram
Function Table
Inputs
Outputs
OE T/R
74F640
74F645
L L Bus B data to Bus A Bus B data to Bus A
L H Bus A data to Bus B Bus A data to Bus B
HX
Z
Z
H = HIGH Voltage Level
L = LOW Voltage Level
X = Don’t Care
Z = High Impedance State
74F640
74F645
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