USB2.0 PHY IC
Level 1
400mV
Differential
Point 3
Point 4
0
Point 1
Point 2
Differential
Point 5
Point 6
-400mV
Differential
Level 2
Unit Interval
100%
0%
Figure 6.4 Eye Pattern for Transmit Waveform and Eye Pattern Definition
.
Table 6.6 Eye Pattern for Transmit Waveform and Eye Pattern Definition
TIME
(% OF UNIT INTERVAL)
VOLTAGE LEVEL (D+, D-)
Level 1
Level 2
525mV in UI following a transition,
N/A
475mV in all others
-525mV in UI following a transition,
-475mV in all others
N/A
0V
7.5% UI
Point 1
Point 2
Point 3
Point 4
Point 5
Point 6
0V
92.5% UI
37.5% UI
62.5% UI
37.5% UI
62.5% UI
300mV
300mV
-300mV
-300mV
The eye pattern in Figure 6.5 defines the receiver sensitivity requirements for a hub (signal applied at
test point TP2 of Figure 6.3) or a device without a captive cable (signal applied at test point TP3 of
Figure 6.3). The corresponding signal levels and timings are given in Table 6.7. Timings are given as
a percentage of the unit interval (UI), which represents the nominal bit duration for a 480 Mbit/s
transmission rate.
SMSC GT3200, SMSC USB3250
Revision 1.3 (10-05-04)
DATA1S6HEET
SMSC [ SMSC CORPORATION ]
