74LCX16821 Datasheet, PDF (2/8 Pages) Fairchild Semiconductor – Low Voltage 20-Bit D-Type Flip-Flop with 5V Tolerant Inputs and Outputs

Connection Diagram
Truth Tables
Functional Description
The LCX16821 contains twenty D-type flip-flops with 3-
STATE standard outputs. The device is byte controlled with
each byte functioning identically, but independent of the
other. Control pins can be shorted together to obtain full
20-bit operation. The following description applies to each
byte. The twenty flip-flops will store the state of their indi-
vidual D inputs that meet the setup and hold time require-
Logic Diagram
CLK₁
X


L or H
Inputs
OE₁
H
L
L
L
D₀–D₉
X
L
H
X
Outputs
O₀–O₉
Z
L
H
O₀
CLK₂
X


L or H
Inputs
OE₂
H
L
L
L
D₁₀–D₁₉
X
L
H
X
Outputs
O₁₀–O₁₉
Z
L
H
O₀
H = HIGH Voltage Level
L = LOW Voltage Level
X = Immaterial
Z = High Impedance
O0 = Previous O0 before LOW-to-HIGH transition of Clock
= LOW-to-HIGH transition
ments on the LOW-to-HIGH Clock (CLK) transition. The 3-
STATE standard outputs are controlled by the Output
Enable (OE_n) input. When OE_n is LOW, the standard out-
puts are in the 2-state mode. When OE_n is HIGH, the stan-
dard outputs are in the high impedance mode but this does
not interfere with entering new data into the flip-flops.
Please note that this diagram is provided only for the understanding of logic operations and should not be used to estimate propagation delays.
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