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OBUFE, 4, 8, 16

3-State Output Buffers with Active-High Output Enable

Element
XC3000
XC4000E
XC4000X
XC5200
XC9000
Spartan
SpartanXL
Virtex
OBUFE
Macro
Macro
Macro
Macro
Primitive
Macro
Macro
Macro
OBUFE4,
OBUFE8,
OBUFE16
Macro
Macro
Macro
Macro
Macro
Macro
Macro
Macro

figures/x3787n.gif

figures/x3794n.gif

figures/x3806n.gif

figures/x3818n.gif

OBUFE, OBUFE4, OBUFE8, and OBUFE16 are 3-state buffers with inputs I, I3 - I0, I7 - I0, and I15-I0, respectively; outputs O, O3 - O0, O7 - O0, and O15-O0, respectively; and active-High output enable (E). When E is High, data on the inputs of the buffers is transferred to the corresponding outputs. When E is Low, the output is High impedance (off or Z state). An OBUFE isolates the internal circuit and provides drive current for signals leaving a chip. An OBUFE output is connected to an OPAD or an IOPAD. An OBUFE input is connected to the internal circuit.

Inputs
Outputs
E
I
O
0
X
Z
1
1
1
1
0
0

Figure 8.2 OBUFE Implementation XC3000, XC4000, XC5200, Spartans, Virtex

Figure 8.3 OBUFE8 Implementation XC3000, XC4000, XC5200, XC9000, Spartans, Virtex

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