QADC64E Legacy Mode Operation
MPC561/MPC563 Reference Manual, Rev. 1.2
Freescale Semiconductor
13-77
Figure 13-55. Input Signal Subjected to Positive Stress
The current into the signal (I
INJN
or I
INJP
) under negative or positive stress is determined by the following
equations:
Eqn. 13-2
Eqn. 13-3
where:
V
STRESS
= Adjustable voltage source
V
EB
= Parasitic PNP emitter/base voltage
(refer to V
NEGCLAMP
in
Appendix F, “Electrical Characteristics
”)
V
BE
= Parasitic NPN base/emitter voltage
(refer to V
NEGCLAMP
in
Appendix F, “Electrical Characteristics
”)
R
STRESS
= Source impedance
(10-k
Ω
resistor in
on stressed channel)
R
SELECTED
= Source impedance on channel selected for conversion
The current into (I
IN
) the neighboring signal is determined by the K
N
(current coupling ratio) of the
parasitic bipolar transistor (K
N
<< 1). The I
IN
can be expressed by the following equation:
I
IN
= - K
N
* I
INJ
where I
INJ
is either I
INJN
or I
INJP
.
A method for minimizing the impact of stress conditions on the QADC64E is to strategically allocate
QADC64E inputs so that the lower accuracy inputs are adjacent to the inputs most likely to see stress
conditions.
Also, suitable source impedances should be selected to meet design goals and minimize the effect of stress
conditions.
QADC64E PAR
R
STRESS
R
SELECTED
Adjacent
10K
Signal Under
PARASITIC
I
INJP
I
IN
+
Stress
V
STRESS
DEVICE
signal
V
IN
V
DDA
AN
n
AN
n+1
I
INJN
V
STRESS
V
BE
–
(
)
–
R
STRESS
------------------------------------------------------
=
I
INJP
V
STRESS
V
EB
–
V
DDA
–
R
STRESS
----------------------------------------------------------------------
=
Summary of Contents for MPC561
Page 84: ...MPC561 MPC563 Reference Manual Rev 1 2 lxxxiv Freescale Semiconductor...
Page 144: ...Signal Descriptions MPC561 MPC563 Reference Manual Rev 1 2 2 46 Freescale Semiconductor...
Page 206: ...Central Processing Unit MPC561 MPC563 Reference Manual Rev 1 2 3 62 Freescale Semiconductor...
Page 302: ...Reset MPC561 MPC563 Reference Manual Rev 1 2 7 14 Freescale Semiconductor...
Page 854: ...Time Processor Unit 3 MPC561 MPC563 Reference Manual Rev 1 2 19 24 Freescale Semiconductor...
Page 968: ...Development Support MPC561 MPC563 Reference Manual Rev 1 2 23 54 Freescale Semiconductor...
Page 1144: ...Internal Memory Map MPC561 MPC563 Reference Manual Rev 1 2 B 34 Freescale Semiconductor...
Page 1212: ...TPU3 ROM Functions MPC561 MPC563 Reference Manual Rev 1 2 D 60 Freescale Semiconductor...
Page 1216: ...Memory Access Timing MPC561 MPC563 Reference Manual Rev 1 2 E 4 Freescale Semiconductor...