USB 2.0 High-Speed 4-Port Hub Controller

Datasheet

Chapter 6 AC Specifications

6.1Oscillator/Clock

Crystal: Parallel Resonant, Fundamental Mode, 24 MHz ±350ppm.

External Clock: 50% Duty cycle ± 10%, 24/48 MHz ± 350ppm, Jitter < 100ps rms.

X T A L 1

(C S 1 =

C B + C XTA L )

C1

C rystal

C L1M eg

C 2

 

X TA L2

 

 

 

 

(C S2 =

 

 

C B + C XTA L )

Figure 6.1 Typical Crystal Circuit

Note: CB equals total board/trace capacitance.

(C1 + CS1) x (C2 + CS2)

= CL

(C1 + CS1 + C2 + CS2)

Figure 6.2 Formula to find value of C1 and C2
6.1.1SMBus 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").

6.1.2I2C EEPROM:

Frequency is fixed at 58.6KHz ± 20%.

6.1.3USB 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.

SMSC USB2514

47

Revision 1.98 (11-19-07)

 

DATASHEET