Digi NS9750 Uživatelský manuál stáhnout pdf (Strana 78)

USB timing

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NS9750B-A1 Datasheet 03/2006

USB timing

Table 36 and Table 37 describe the values shown in the USB timing diagrams.

Notes:

1 Load shown in "USB full speed load."

2 U1/U2.

3 Includes resistance of 27 ohm ±2 ohm external series resistor.

4 Load shown in "USB low speed load."

5 Excluding the first transition from the idle state.

USB differential data timing

Parameter Description Min Max Unit Notes

U1 Rise time (10%–90%) 4 20 ns 1

U2 Fall time (10%–90%) 4 20 ns 1

U3 Differential rise and fall time matching 90 111.11 % 2, 5

U4 Driver output resistance 28 44 ohms 3

Table 36: USB full speed timing parameters

Parameter Description Min Max Unit Notes

U1 Rise time (10%–90%) 75 300 ns 4

U2 Fall time (10%–90%) 75 300 ns 4

U3 Differential rise and fall time matching 80 125 % 2, 5

Table 37: USB low speed timing parameters

10%

90%

10%

usb_dp

usb_dm

1 2 ... 73 74 75 76 77 78 79 80 81 82 83 ... 87 88

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Digi NS9750 Uživatelský manuál Strana 78