MPC564EVB Freescale Semiconductor, MPC564EVB Datasheet - Page 539

• Manufacturer Part Number: MPC564EVB
• Description: KIT EVAL FOR MPC561/562/563/564
• Manufacturer: Freescale Semiconductor
• Type: Microcontrollerr

Specifications of MPC564EVB

• Contents: Module Board, Installation Guide, Power Supply, Cable, Software and more
• Processor To Be Evaluated: MPC56x
• Data Bus Width: 32 bit
• Interface Type: RS-232, Ethernet
• For Use With/related Products: MPC561, 562, 563, 564
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

13.7.5.2
The values for R
C
disconnecting the internal circuitry from the external circuitry. Assume that the initial voltage across C
zero. As C
charge time:
As t approaches infinity, V
1/2 of a count is equal to 1/2048 full-scale value. Assuming worst case (V
shows the required time for C
conversions.
The external circuit described in
component of the external signal must take the characteristics of this filter into account.
13.7.5.3
A series resistor limits the current to a signal, therefore input leakage acting through a large source
impedance can degrade A/D accuracy. The maximum input leakage current is specified in
“Electrical
range from 125° C to 50° C, the leakage current is halved for every 8 – 12° C reduction in temperature.
Assuming V
voltage. A typical input leakage of 200 nA acting through 10 kΩ of external series resistance results in an
error of 0.4 count (2.0 mV). If the source impedance is 100 kΩ and a typical leakage of 100 nA is present,
an error of two counts (10 mV) is introduced.
Freescale Semiconductor
F
to the source voltage level (V
F
Characteristics.” Input leakage is greater at higher operating temperatures. In the temperature
charges, the voltage across it is determined by the following equation, where t is the total
RH
Table 13-24
Filter Capacitor
Settling Time for the External Circuit
Error Resulting from Leakage
The following times are completely independent of the A/D converter
architecture (assuming the QADC64E is not affecting the charging).
– V
Table 13-24. External Circuit Settling Time to 1/2 LSB (10-Bit Conversions)
SRC
.001 µF
100 pF
.01 µF
.1 µF
(CF)
1 µF
RL
, R
= 5.12 V, one count (assuming 10-bit resolution) corresponds to 5 mV of input
F
and C
is based on the RC network in
CF
will equal V
F
to charge to within 1/2 of a count of the actual source voltage during 10-bit
F
in the external circuitry determine the length of time required to charge
SRC
MPC561/MPC563 Reference Manual, Rev. 1.2
Table 13-24
760 µs
760 ns
V CF
7.6 µs
100 Ω
76 µs
76 ns
). At time t = 0, V
=
V SRC 1 e
SRC
. (This assumes no internal leakage.) With 10-bit resolution,
is a low-pass filter. A user interested in measuring an AC
⎛
⎜
⎜
⎜
⎜
⎜
⎝
Source Resistance (R
–
NOTE
7.6 ms
760 µs
760 ns
7.6 µs
76 µs
1 kΩ
⎛
⎜
⎜
⎝
---------------------------------------------------------- -
(
R F
SRC
+
Figure
R SRC
t –
changes in
)C
13-52.
F
⎞
⎟
⎟
⎠
7.6 ms
760 µs
F
10 kΩ
76 ms
7.6 µs
⎞
⎟
⎟
⎟
⎟
⎟
⎠
76 µs
+ R
Figure 13-52
SRC
)
SRC
= full scale),
QADC64E Legacy Mode Operation
100 kΩ
760 ms
7.6 ms
760 µs
76 ms
76 µs
while S1 is open,
Appendix F,
Table 13-24
Eqn. 13-1
13-75
F
is