AN1058 Freescale Semiconductor / Motorola, AN1058 Datasheet - Page 23

• Manufacturer Part Number: AN1058
• Description: Reducing A/D Errors in Microcontroller Applications
• Manufacturer: Freescale Semiconductor / Motorola

AN1058
MOTOROLA
with the bypass cap. Out-of-spec ADC errors were totally eliminated
(see
range of sensitivity for the ADC result range of interest was changed on
the logic analyzer. By changing the range to show values between (94)
and (96)
results of this measurement run are shown in
Note: Readings are rounded to nearest 1% value.
READ ING
R EADING
A1–A8
A9–B0
B1–B8
B9–C0
C1–FF
A1–A8
A9–B0
B1–B8
B9–C0
C1–FF
(H EX)
81–98
99–A0
94–96
97–A0
(HEX)
Freescale Semiconductor, Inc.
ADC
0–80
0–93
ADC
Figure
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FR EQ .
FR EQ .
100 %
100 %
0 %
0 %
0 %
0 %
0 %
0 %
0 %
0 %
0 %
0 %
0 %
0 %
0 %
0 %
Figure 12. V
, inclusively, the 1 LSB spec could be observed directly. The
12(a)). To check the thoroughness of this last circuit fix, the
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EXPANDED SCALE
EXPANDED SCALE
0
0
CO ND ITIO NS: D IO DE IN V
TO TAL SAM PLES = 167.9 K
C ON DITIO NS: FIN AL CIR CUIT
TOTAL SAM PLES = 167.9 K
5
5
10
10
DD
(b) Tightened ADC Range
Diode and Tightened ADC Range
20
20
(a) Diode in V
DD
30
30
PERCENT OCCURRENCE
PERCENT OCCURRENCE
40
40
DD
50
50
Figure
60
60
M 68HC11 INDU STRIAL
M 68H C11 IN DUSTR IAL
12(b)).
70
70
CO NTR O LLER
C ON TRO LLER
The Perfect Circuit
Application Note
80
80
90
90
100
100
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