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MB91401
(9) USB interface
Parameter
Input clock
RISE Time
Fall Time
Differential Rise and Fall
Timing Matching
Driver Output Resistance
UCLK48
UDP
UDM
*1 : The AC characteristics of the USB interface conform to USB Specification Revision 1.1.
*2 : <Driver Characteristics TFR, TFF, TFRFM>
These items specify the differential data signal rise (trise) and fall (tfall) times.
These are defined as the times between 10
For the full-speed buffer, trise and tfall are specified such that the tr/tf ratio falls within 10
radiation.
*3 : <Driver Characteristics ZDRV>
USB full-speed connection is performed via a shielded twisted-pair cable at a characteristic impedance of
90
15 . The USB Standard stipulates that the USB driver's output impedance must be within the range
of 28
to 44 . The USB Standard also stipulates that a discrete serial resistor (R
balance while satisfying the above standard.
The output impedance of the USB I/O buffer on this LSI is about 3
must be 25
to 30
Capacitor CL of 50 pF must be added as well.
64
Symbol
Pin
tucyc
UCLK48
tutfr
UDP, UDM
tutff
UDP, UDM
tutfrfm
UDP, UDM
tzdrv
UDP, UDM
90%
90%
10%
tutfr
to 90
(27
recommended) .
Value
Min
Typ
Max
48*
1
4
20
4
20
90
111.11
28
44
tucyc
10%
tutff
of the output signal voltage.
to 19 . Serial resistor R
Prelminary
2004.11.12
Unit
Remarks
MHz 2500ppm accuracy*
ns
*2
ns
*2
*2
*3
to minimize RFI
) must be added to have
S
to be added
S
1
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