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 , 33 , 38 , or 50 . 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).