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GTL+ INTERFACE SPECIFICATIONS
An example of the simplest Flight Time measurement is shown in Figure 8-5. The receiver
specification assumes that the signal maintains an edge rate greater than or equal to 0.3V/ns
at the receiver chip pad in the overdrive region from V
edge and that there are no signal quality violations after the input crosses V
The Flight Time measurement is similar for a simple Hi-to-Lo transition. Notice that timing
is measured at the driver and receiver pins while signal integrity is observed at the receiver
chip pad. When signal integrity at the pad violates the guidelines of this specification, and
adjustments need to be made to flight time, the adjusted flight time obtained at the chip pad
can be assumed to have been obtained at the package pin, usually with a small timing error
penalty.
Driver Pin into
Test Load
V
TT
V
+0.2
REF
V
REF
V
OL
8-8
Driver Pin into
System Load
Flight Time
Figure 8-5. Measuring Nominal Flight Time
to V
REF
REF
Overdrive Region
At Receiver Pin
Time
+200 mV for a rising
at the pad.
REF
000949
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