Universal Serial Bus Specification Revision 2.0
185
Table 7-12. Cable Characteristics (Note 14)
Parameter
Symbol Conditions
Min
Max Units V BUS Voltage drop for detachable cables V BUSD Section 7.2.2125mV GND Voltage drop (for all cables)
V GNDD Section 7.2.2125mV Differential Cable Impedance (full-/high-speed)
Z O (90 Ω ±15%);76.5103.5ΩCommon mode cable
impedance (full-/high-speed)Z CM
(30 Ω ±30%);21.039.0
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Ω
上祖Cable Delay (one way)
Full-/high-speed Low-speed T FSCBL T LSCBL Section 7.1.16
偏角法
2618ns ns Cable Skew
T SKEW Section 7.1.3100ps Unmated Contact Capacitance C UC
Section 6.7
2
pF
Cable loss
Specified by table and graph in Section 7.1.17卓老师
描写梨花的诗句Note 1: Measured at A plug.Note 2: Measured at A receptacle.Note 3: Measured at B receptacle.Not
e 4: Measured at A or B connector.Note 5: Measured with RL of 1.425 k Ω to 3.6 V.Note 6: Measured with RL of 14.25 k Ω to GND.
Note 7: Timing difference between the differential data signals.Note 8: Measured at crossover point of differential data signals.
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Note 9: The maximum load specification is the maximum effective capacitive load allowed that meets the target
V BUS drop of 330 mV.Note 10: Excluding the first transition from the Idle state.Note 11: The two transitions should be a (nominal) bit time apart.Note 12: For both transitions of differential signaling.Note 13: Must accept as valid EOP.
Note 14: Single-ended capacitance of D+ or D- is the capacitance of D+/D- to all other conductors and, if prent,
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shield in the cable. That is, to measure the single-ended capacitance of D+, short D-, VBUS, GND, and the shield line together and measure the capacitance of D+ to the other conductors.Note 15: For high power devices (non-hubs) when enabled for remote wakeup.如何制作系统u盘
