XC2234N INFINEON [Infineon Technologies AG], XC2234N Datasheet - Page 87

• Manufacturer Part Number: XC2234N
• Description: 16/32-Bit Single-Chip Microcontroller with 32-Bit Performance XC2000 Family / Value Line
• Manufacturer: INFINEON [Infineon Technologies AG]

The timing in the AC Characteristics refers to TCSs. Timing must be calculated using the
minimum TCS possible under the given circumstances.
The actual minimum value for TCS depends on the jitter of the PLL. Because the PLL is
constantly adjusting its output frequency to correspond to the input frequency (from
crystal or oscillator), the accumulated jitter is limited. This means that the relative
deviation for periods of more than one TCS is lower than for a single TCS (see formulas
and
This is especially important for bus cycles using waitstates and for the operation of
timers, serial interfaces, etc. For all slower operations and longer periods (e.g. pulse train
generation or measurement, lower baudrates, etc.) the deviation caused by the PLL jitter
is negligible.
The value of the accumulated PLL jitter depends on the number of consecutive VCO
output cycles within the respective timeframe. The VCO output clock is divided by the
output prescaler K2 to generate the system clock signal
is K2 × T, where T is the number of consecutive
The maximum accumulated jitter (long-term jitter) D
D
This maximum value is applicable, if either the number of clock cycles T > (
the prescaler value K2 > 17.
In all other cases for a timeframe of T × TCS the accumulated jitter D
D
f
Example, for a period of 3 TCSs @ 33 MHz and K2 = 4:
D
D
= 5.97 × [0.768 × 2 / 26.39 + 0.232]
= 1.7 ns
Example, for a period of 3 TCSs @ 33 MHz and K2 = 2:
D
D
= 7.63 × [0.884 × 2 / 26.39 + 0.116]
= 1.4 ns
Data Sheet
SYS
Tmax
T
max
3
max
3
= 5.97 × [(1 - 0.058 × 4) × (3 - 1) / (0.83 × 33 - 1) + 0.058 × 4]
= 7.63 × [(1 - 0.058 × 2) × (3 - 1) / (0.83 × 33 - 1) + 0.058 × 2]
[ns] = D
Figure
in [MHz] in all formulas.
= ±(220 / (4 × 33) + 4.3) = 5.97 ns (Not applicable directly in this case!)
= ±(220 / (2 × 33) + 4.3) = 7.63 ns (Not applicable directly in this case!)
[ns] = ±(220 / (K2 ×
Tmax
20).
× [(1 - 0.058 × K2) × (T - 1) / (0.83 ×
f
SYS
) + 4.3)
XC2232N, XC2234N, XC2236N, XC2238N
87
f
SYS
Tmax
f
cycles (TCS).
SYS
XC2000 Family / Value Line
f
is defined by:
SYS
- 1) + 0.058 × K2]
. The number of VCO cycles
Electrical Parameters
T
is determined by:
V1.3, 2010-04
f
SYS
/ 1.2) or