Ultra Fast USB 2.0 Memory Stick Flash Media Controller

Datasheet

Chapter 8 AC Specifications

8.1Oscillator/Clock

Crystal: Parallel Resonant, Fundamental Mode, 24 MHz ± 100ppm.

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

XTAL1

(CS1 =

CB + CXTAL )

C1

Crystal CL

1Meg

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

C2

 

 

 

 

 

XTAL2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(CS2 =

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

CB + CXTAL )

Figure 8.1 Typical Crystal Circuit

Note: CB equals total board/trace capacitance.

(C1 + CS1) x (C2 + CS2)

= CL

(C1 + CS1 + C2 + CS2)

Figure 8.2 Formula to Find Value of C1 and C2

SMSC USB2242/USB2242i

21

Revision 1.0 (05-27-08)

DATASHEET