USB2513B-AEZC View Datasheet(PDF) - SMSC -> Microchip
Part Name
Description
MFG CO.
'USB2513B-AEZC' PDF : 63 Pages View PDF
Chapter 7 AC Specifications
USB 2.0 Hi-Speed Hub Controller
Datasheet
7.1
Oscillator/Crystal
Crystal: Parallel resonant, fundamental mode, 24 MHz ±350 ppm
XTAL1
(CS1 = CB1 + CXTAL1 )
C1
C0
Crystal CL
1M
C2
XTAL2
(CS2 = CB2 + CXTAL2 )
Figure 7.1 Typical Crystal Circuit
Table 7.1 Crystal Circuit Legend
SYMBOL
C0
CL
CB
CS
CXTAL
C1
C2
DESCRIPTION
Crystal shunt capacitance
Crystal load capacitance
Total board or trace capacitance
Stray capacitance
XTAL pin input capacitance
Load capacitors installed on OEM
board
IN ACCORDANCE WITH
Crystal manufacturer’s specification (Note 7.1)
OEM board design
SMSC IC and OEM board design
SMSC IC
Calculated values based on Figure 7.2 (Note 7.2)
C1 = 2 x (CL – C0) – CS1
C2 = 2 x (CL – C0) – CS2
Note 7.1
Figure 7.2 Formula to Find the Value of C1 and C2
C0 is usually included (subtracted by the crystal manufacturer) in the specification for CL
and should be set to 0 for use in the calculation of the capacitance formulas in Figure 7.2.
However, the PCB itself may present a parasitic capacitance between XTALIN and
XTALOUT. For an accurate calculation of C1 and C2, take the parasitic capacitance
between traces XTALIN and XTALOUT into account.
Note 7.2 Each of these capacitance values is typically around 18 pF.
Revision 2.2 (02-17-12)
56
DATASHEET
SMSC USB251xB/xBi
Share Link: 
