SPC5646CCF0MLU1 Freescale Semiconductor, SPC5646CCF0MLU1 Datasheet - Page 74

• Manufacturer Part Number: SPC5646CCF0MLU1
• Description: 32-bit Microcontrollers - MCU 3M FLASH,25 6K RAM,CSE
• Manufacturer: Freescale Semiconductor

Specifications of SPC5646CCF0MLU1

• Rohs: yes
• Core: e200
• Processor Series: MPC5646C
• Data Bus Width: 32 bit
• Maximum Clock Frequency: 120 MHz
• Program Memory Size: 3 MB
• Data Ram Size: 256 KB
• On-chip Adc: Yes
• Operating Supply Voltage: 0.3 V to 6.2 V
• Operating Temperature Range: - 40 C to + 125 C
• Package / Case: LQFP-176
• Mounting Style: SMD/SMT
• A/d Bit Size: 10 bit, 12 bit
• A/d Channels Available: 33
• Interface Type: CAN, I2C, SCI, SPI
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 40 C
• Number Of Programmable I/os: 147
• Number Of Timers: 32
• Program Memory Type: Flash
• Supply Voltage - Max: 6.2 V
• Supply Voltage - Min: 0.3 V

Electrical Characteristics
In particular two different transient periods can be distinguished:
This relation can again be simplified considering C
converter circuitry has been designed to be robust also in very worst case : the sampling time T
internal time constant.
The charge of C
the following equation
In this case, the time constant depends on the external circuit: in particular imposing that the transient is completed well before
the end of sampling time T
Of course, R
and R
transfer transient) will be much higher than V
already charged at V
The two transients above are not influenced by the voltage source that, due to the presence of the R
provide the extra charge to compensate the voltage drop on C
the filter is very high with respect to the sampling time (T
74
•
•
F
(filter resistance). Being C
is supposed initially completely discharged):considering a worst case (since the time constant in reality would be
faster) in which C
and the time constant is
A second charge transfer involves also C
RL: again considering the worst case in which C
would be faster), the time constant is:
A first and quick charge transfer from the internal capacitance C
L
shall be sized also according to the current limitation constraints, in combination with R
P1
and C
A1
):
P2
P2
S
V A2
is redistributed on C
, a constraints on R
is reported in parallel to C

F

C S C P1 C P2 C F
definitively bigger than C
V A1
MPC5646C Microcontroller DataSheet, Rev. 5.1
+
8.5


 2

A1
+
C S
 1
 1
L
S
. The following equation must be respected (charge balance assuming now C
 2 R L
=
,determining a new value of the voltage V
F
sizing is obtained:
=
+

8.5
S
(that is typically bigger than the on-chip capacitance) through the resistance

C P1


+
as an additional worst condition. In reality, transient is faster, but the A/D
R SW
R SW

R L
P1

+
P2

S

(call C

). The filter is typically designed to act as anti-aliasing
C P2
C S
+
+
=
and C

P1
R AD
R AD
C S
S
V A C F
, C
+
with respect to the ideal source V

P
C P1
+

P2
=
S
= C


C P1
were in parallel to C
and C
V A


C S T S
+
P1
-------------------- -
C P
C P C S
+
C P2
+
P1

V A1
+ C
«
S
+


C P2
, then the final voltage V
and C
C P1
C S
P2


), the two capacitances C


+

C P1 C P2
P2
C P2
T S
to the sampling capacitance C
+

P1
A1
(since the time constant in reality
+
s
on the capacitance according to
C S
is always much longer than the
A

; the time constant R
A2
F
C
(at the end of the charge
F
S
P
filter, is not able to
(source impedance)
and C
S
are in series,
S
occurs (C
Freescale
Eqn. 10
Eqn. 5
Eqn. 6
Eqn. 7
Eqn. 8
Eqn. 9
F
C
F
of
S
S