SMSC USB2514 - Manual (Page 47)

USB 2.0 High-Speed 4-Port Hub Controller
Datasheet
SMSC USB2514 47 Revision 1.98 (11-19-07)
DATASHEET
Chapter 6 AC Specifications
6.1 Oscillator/Clock
Crystal: Parallel Resonant, Fundamental Mode, 24 MHz
±350ppm.
External Clock: 50% Duty cycle
± 10%, 24/48 MHz ± 350ppm, Jitter < 100ps rms.
Figure 6.1 Typical Crystal Circuit
Note: C
B
equals total board/trace capacitance.
Figure 6.2 Formula to find value of C
1
and C
2
6.1.1 SMBus Interface:
The SMSC Hub conforms to all voltage, power, and timing characteristics and specifications as set
forth in the SMBus 1.0 Specification for Slave-Only devices (except as noted in
Section 4.4, "SMBus
Slave Interface" ).
6.1.2 I2C EEPROM:
Frequency is fixed at 58.6KHz
± 20%.
6.1.3 USB 2.0
The SMSC Hub conforms to all voltage, power, and timing characteristics and specifications as set
forth in the USB 2.0 Specification. Please refer to the USB 2.0 Specification for more information.
X T A L 1
(C
S 1 =
C
B
+ C
X T A L
)
X T A L 2
(C
S 2 =
C
B
+ C
X T A L
)
C
1
C
2
C
L
1 M e g
C ry s ta l
(C
1
+ C
S1
) x (C
2
+ C
S2
)
(C
1
+ C
S1
+ C
2
+ C
S2
)
C
L
=