MAC7100CVF Motorola, MAC7100CVF Datasheet - Page 16

• Manufacturer Part Number: MAC7100CVF
• Description: MAC7100 Microcontroller Family Hardware Specifications
• Manufacturer: Motorola

Electrical Characteristics
3.8.2.1
The basic functionality of the PLL is shown in Figure 3. With each transition of the clock f
from the reference clock f
is done continuously with no abrupt changes in the clock output frequency. Noise, voltage, temperature and
other factors cause slight variations in the control loop resulting in a clock jitter. This jitter affects the real
minimum and maximum clock periods as illustrated in Figure 4. It is important to note that the pre-scaler used
by timers and serial modules will eliminate the effect of PLL jitter to a large extent.
The relative deviation of t
number of clock periods (N). Thus, jitter is defined as:
For N < 100, the following equation is a good fit for the maximum jitter:
16
Jitter Information
0
J(N)
t
MIN1
t
t
NOM
MAX1
0 1
PRELIMINARY—SUBJECT TO CHANGE WITHOUT NOTICE
MAC7100 Microcontroller Family Hardware Specifications
ref
NOM
Figure 5. Maximum Bus Clock Jitter Approximation
is measured and input voltage to the VCO is adjusted accordingly. The adjustment
1
Freescale Semiconductor, Inc.
For More Information On This Product,
is at its maximum for one clock period, and decreases towards zero for larger
5
J N
( )
Figure 4. Jitter Definitions
Go to: www.freescale.com
=
2
max 1
t
MIN


J N
t
10
MAX
( )
(N)
–
t
-------------------- -
N t
(N)
MAX
=
⋅
------- -
NOM
j
( )
1
N
N
3
+
,
j
2
1
15
–
-------------------- -
N t
t
MIN
⋅
NOM
( )
N
N–1


20
N
cmp
N
, the deviation
MOTOROLA