Datasheet

SCBA015A
7–24
Fast GTLP Backplanes With the GTLPH1655
Termination Voltage, V
TT
There are various rules and techniques regarding proper line termination that should be
observed for a successful development using SN74GTLPH1655.
The termination voltage (V
TT
) should be derived from a voltage regulator. The current
requirements, e.g., up to 100 mA per output, must be observed. There are various voltage
regulators available that meet these requirements. Depending on the application, the regulators
should be situated either directly on the backplane or on the module boards connected to it.
If several signal lines are switched simultaneously, considerable current fluctuations may occur
at the termination voltage. For this reason, bypass capacitors should be provided close to the
termination resistors (Figure 14).
R
TT
= Termination Resistor
C
TT
= Bypass Capacitor
V
TT
= Termination Voltage
Signal Line
Signal Line
Signal Line
Signal Line
GND
R
TT
R
TT
R
TT
R
TT
C
TT
V
TT
Figure 14. Proposed Layout of Termination Resistors and Bypass Capacitor on a Circuit Board