MOTOROLA
MC68341 USER’S MANUAL
12-7
CLOCK SPECIFICATIONS - External Clock With PLL Mode
3.3 V or 5.0 V
5.0 V
16.78 MHz
25.16 MHz
Num.
Characteristic
Symbol
Min
Max
Min
Max
Unit
System Frequency
External Clock with PLL Mode
fsys
0.1
16.78
0.1
25.16
MHz
1C
External Clock Input Period
tEXTcyc 59.6
10
S
39.7
10
Sns
External Clock Duty Cycle
20
80
20
80
%
External Clock Input Period with
÷2
tEXTcyc TBD
—
TBD
—
ns
External Clock Duty Cycle with
÷2
TBD
—
TBD
—
%
VCO Frequency Range
fVCO
0.1
33.6
0.1
51.2
MHz
PLL Start-up Time1
trc
—
20
—
20
ms
Limp Mode CLKOUT Frequency
flimp
—
kHz
CLKOUT stability 2
CLK
—
±1
—
±1
%
CLKOUT Duty Cycle
47
53
47
53
%
2C, 3C
CLKOUT Pulse Width
tEXTCW
28
—
19
—
ns
4,5
CLKOUT Rise and Fall Times
tCrf
—
5
—
4
ns
Clock Input to CLKOUT Skew (Rising
Edges)
—
±5
—
±5
ns
NOTES:
1.
Assumes that a stable VCCSYN is applied, that an external filter capacitor with a value of 0.1 F is attached to
the XFC pin, and that the crystal oscillator is stable. This specification also applies to the period required for PLL
lock after changing the W or Y frequency control bits in the synthesizer control register (SYNCR) while the PLL is
running, and to the period required for the clock to lock after exiting LPSTOP.
2.
CLKOUT stability is the average deviation from programmed frequency measured at maximum f sys.
Measurement is made with a stable external clock input applied using the PLL.
CLOCK SPECIFICATIONS - External Clock Mode (Without PLL)
3.3 V or 5.0 V
5.0 V
16.78 MHz
25.16 MHz
Num.
Characteristic
Symbol
Min
Max
Min
Max
Unit
System Frequency1
External Clock Without PLL Mode
fsys
dc
16.78
dc
25.16
MHz
1B
External Clock Input Period
tEXTcyc 59.6
—
39.7
—
ns
External Clock Pulse Width
TBD
—
TBD
—
ns
External Clock Input Period with
÷2
tEXTcyc TBD
—
TBD
—
ns
External Clock Pulse Width with
÷2
TBD
—
TBD
—
ns
2B, 3B9 CLKOUT Pulse Width
tEXTCW
TBD
—
TBD
—
ns
4,5
CLKOUT Rise and Fall Times
tCrf
—
5
—
4
ns
Clock Input to CLKOUT Skew (Rising
Edges)
TBD
ns
1.
All internal registers retain data at 0 Hz.
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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