TRK-USB-MPC5643L Freescale Semiconductor, TRK-USB-MPC5643L Datasheet - Page 95

• Manufacturer Part Number: TRK-USB-MPC5643L
• Description: Development Boards & Kits - Other Processors StarTrakMiniUSG MPC5643L
• Manufacturer: Freescale Semiconductor

Specifications of TRK-USB-MPC5643L

• Rohs: yes
• Product: Starter Kits
• Tool Is For Evaluation Of: MPC5643L
• Core: Five Stage Pipeline
• Interface Type: LIN, DSPI
• Operating Supply Voltage: 3 V to 3.6 V
• Data Bus Width: 32 bit, 64 bit
• Description/function: Starter Kit for MPC5643L
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 40 C
• For Use With: MPC5643L

Equation 4
and R
A second aspect involving the capacitance network shall be considered. Assuming the three capacitances C
initially charged at the source voltage V
installed when the sampling phase is started (A/D switch close).
In particular two different transient periods can be distinguished:
Freescale Semiconductor
•
AD
) can be neglected with respect to external resistances.
A first and quick charge transfer from the internal capacitance C
is supposed initially completely discharged): considering a worst case (since the time constant in reality would be
generates a constraint for external network design, in particular on resistive path. Internal switch resistances (R
V
A
Source
V
V
V
V
CS
A
A2
A1
R
R
C
R
R
R
C
C
R
S
F
F
L
SW1
AD
P
S
S
Figure 9. Transient Behavior during Sampling Phase
1
EXTERNAL CIRCUIT
Source Impedance
Filter Resistance
Filter Capacitance
Current Limiter Resistance
Channel Selection Switch Impedance
Sampling Switch Impedance
Pin Capacitance (two contributions, C
Sampling Capacitance
Voltage Transient on C
MPC5643L Microcontroller Data Sheet, Rev. 8.1
A
(refer to the equivalent circuit reported in
R
Filter
F
Figure 8. Input Equivalent Circuit
2
C
F
Current Limiter
R
L
S
T
S
P1
and C
V <0.5 LSB
t
C
P1
P2

)
P1
1

< (R
2
and C
= R
V
INTERNAL CIRCUIT SCHEME
DD
SW
L

(C
P2
+ R
S
Figure
to the sampling capacitance C
Selection
+ C
Channel
R
AD
P1
SW1
) C
C
+ C
P2
8): A charge sharing phenomenon is
S
P2
<< T
)
Sampling
S
R
AD
Electrical characteristics
C
S
F
, C
P1
S
and C
occurs (C
P2
are
SW
95
S