Datasheet
Termination Cards
7–327
GTLP EVM Board Typical Test and Setup Configuration
2.7 Termination Cards
Because proper backplane termination has a large effect on signal integrity
and is investigated easily, Group 1 has removable termination cards on the
back of the backplane (see Figure 2–13). The termination cards are identical,
except for the resistor values that are 25 Ω, 33 Ω, 38 Ω, or 50 Ω. One bypass
capacitor is mounted with every other termination resistor to limit voltage
fluctuations. The termination cards provide a method of varying the
termination resistance to only Group 1 data lines. These termination resistors
connect to the V
TT
supply (1.5 V because GTLP levels are used).
Figure 2–13. Termination Card Location (Left) and Close-Up View (Right)
Match Dots
Connector Key.
Can be reversed, so
ensure that dots are
on the same side.
The termination cards have a four-layer stackup. The stackup is signal layer,
V
CC
plane, ground plane, and signal layer (see Table 2–4).