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Hold time for GTL+, T
The minimum time from the clock pin of the receivers crossing of the 1.5V
level to the receiver input signal pin crossing of V
that the input buffer has captured new data at the receiver input signal pin,
given an infinite setup time.
Strictly speaking, hold time must be determined when the input barely meets minimum setup
time (see definition of setup time above). However, for current GTL+ systems, setup time is
expected to be met, well beyond the minimum required in cases where hold is critical. This is
because hold is critical when the receiver is very close to the driver. In such cases, the signal
will arrive at the receiver shortly after the clock, hence meeting setup time with comfortable
margin.
V
+0.2
REF
V
REF
V
–0.2
REF
V
start
Figure 8-11. Standard Input Lo-to-Hi Waveform for Characterizing Receiver Setup Time
, is defined as:
HOLD
GTL+ INTERFACE SPECIFICATIONS
, which guarantees
REF
1.5V Clk Ref
Clock
T
SU
Time
000957
8-17
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