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EP2S180F1020C4 Datasheet, PDF (756/768 Pages) Altera Corporation – Stratix II Device Handbook, Volume 1 | |||
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Termination Schemes
Figure 11â23. Simple Parallel Fly-By Termination
Source
Zo = 50 Ω
Receiver / Load
Pad
RT = Zo
Thevenin Parallel Termination
An alternative parallel termination scheme uses a Thevenin voltage
divider (see Figure 11â24). The RT is split between R1 and R2, which equals
the line impedance when combined.
Figure 11â24. Thevenin Parallel Termination
VCC
Stub
R1
S
Zo= 50 Ω
L
R1 R2 = Zo
R2
As noted in the previous section, stub length is dependent on signal rise
and fall time and should be kept to a minimum. If your design requires a
long termination line between the terminator and receiver, use fly-by
termination or Thevenin fly-by termination (see Figures 11â23 and
11â25).
11â20
Stratix II Device Handbook, Volume 2
Altera Corporation
May 2007
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