AM186CC-25KI\W C AMD (ADVANCED MICRO DEVICES), AM186CC-25KI\W C Datasheet - Page 42

• Manufacturer Part Number: AM186CC-25KI\W C
• Manufacturer: AMD (ADVANCED MICRO DEVICES)

Specifications of AM186CC-25KI\W C

• Lead Free Status / Rohs Status: Not Compliant

Crystal-Driven Clock Source
The internal oscillator circuit is designed to function
with an external parallel-resonant fundamental mode
crystal. The crystal frequency can vary from 8 to
40 MHz, depending on the PLL mode selected and de-
sired system frequency.
When selecting a crystal, the load capacitance should
always be specified (C
variance in the oscillation frequency from the desired
specified value (resonance). The load capacitance and
the loading of the feedback network have the following
relationship:
where C
Table 6 shows crystal parameter values. Figure 10
shows the system clocks using an external crystal and
the integrated oscillator. The specific values for C
C
dependent on the characteristics of the chosen crystal
and board design.
42
2
4x Mode
2x Mode
1x Mode
C
must be determined by the designer and are
Bypass
L
Mode
=
PLL
0 MHz
System Operating Frequency
(C
S
(C
Figure 9. Suggested System Clock Frequencies, Clock Modes, and Crystal Frequencies
is the stray capacitance of the circuit.
1
1
1
The crystal oscillator is not guaranteed above 40 MHz.
+ C
C
0-MHz to 24-MHz Xtal or Clock
2
2
)
)
+ C
PLL Bypass Mode
16 MHz
S
L
). This value can cause
Am186™CC Communications Controller Data Sheet
20 MHz
16-MHz to 40-MHz Xtal or Clock
24 MHz
1
and
1x Mode
8-MHz to 25-MHz Xtal or Clock
30 MHz
Figure 10. External Interface to Support Clocks—
Parameter
Frequency
ESR
8–24 MHz
24–50 MHz
Load Capacitance
32 MHz
C1
8-MHz to 12.5-MHz Xtal or Clock
1
Table 6. Crystal Parameters
Fundamental Mode Crystal
2x Mode
C2
40 MHz
Xtal
Value
Min.
20
20
10
X2/USBX2
8
X1/USBX1
Value
Max.
40
90
60
—
4x Mode
50 MHz
Units
ohms
ohms
MHz
pF