Datasheet

Receiver Cards
7–338
2.12 Receiver Cards
Receiver cards place a load on the backplane and provide a point to monitor
the signals. There are two types of receiver cards: one that has built-in monitor
points, and one with no monitor points. Either type can be placed in any slot
in the backplane, typically with the monitored receiver card placed in the slots
under observation. There is a monitor point for only one bit per group. Only a
few receiver cards have monitor points because the capacitance added by the
monitor point affects backplane signal integrity. Minimal use of the monitored
receiver card is encouraged because of the increased loading this card
causes.
Receiver cards have GTLP devices hardwired for clocked storage in the
B-to-A direction. Data is latched on the rising edge of the GTLP latch clock. The
latch clock comes from the system clock when the MODESEL line is high, and
from the GTLP clock when the MODESEL line is low. The receiver card is a
six-layer PCB with two signal layers, a V
CC
plane, a ground plane, then two
signal layers. The GTLP data and clock stub lines are approximately 1 in. in
length. Stackup is shown in Table 2–7.
Table 2–7. Receiver-Card Stackup
Trace Name Use Layer
Copper
Weight (oz)
Physical
Representation
Dielectric
Height (in.)
Dielectric
Name
Top Data signal 1 0.5
0.004 B stage
Internal signal 2 Data signal 2 1
0.004 Core
V
CC
plane V
CC
plane 3 1
0.004 B stage
Ground plane Ground plane 4 1
0.004 Core
Internal signal 3 Data signal 5 1
0.004 B stage
Bottom
Data signal 6 1