NXP Semiconductors MPC5777M - ADC Specifications; ADC Input Description

MPC5777M Microcontroller Data Sheet, Rev. 6
Electrical characteristics
NXP Semiconductors52
3.10 ADC specifications
3.10.1 ADC input description
Figure 14 shows the input equivalent circuit for fast SARn channels.
Figure 14. Input equivalent circuit (Fast SARn channels)
Figure 15 shows the input equivalent circuit for SARB channels.
Figure 15. Input equivalent circuit (SARB channels)
R
SW1
C
P2
C
S
V
DD
Sampling
INTERNAL CIRCUIT SCHEME
R
SW1
Channel Selection Switch Impedance
R
AD
Sampling Switch Impedance
C
P
Pin Capacitance (two contributions, C
P1
and C
P2
)
C
S
Sampling Capacitance
R
CMSW
Common mode switch
R
CML
Common mode resistive ladder
This figure can be used as approximation circuitry for external filtering definition.
C
P1
R
AD
Channel
Selection
Common mode
switch
Common mode
resistive ladder
R
SW1
C
P3
C
S
V
DD
Sampling
R
SW
: Channel Selection Switch Impedance (two contributions R
SW1
and R
SW2
)
R
AD
: Sampling Switch Impedance
C
P
: Pin Capacitance (three contributions, C
P1
, C
P2
and C
P3
)
C
S
: Sampling Capacitance
R
CMSW:
Common mode switch
R
CML
: Common mode resistive ladder
The above figure can be used as approximation circuitry for external filtering definition.
C
P1
R
AD
Channel
Selection
C
P2
Extended
R
SW2
Switch
Common mode
switch
Common mode
resistive ladder
INTERNAL CIRCUIT SCHEME