MC9S12A128 MOTOROLA [Motorola, Inc], MC9S12A128 Datasheet - Page 66

• Manufacturer Part Number: MC9S12A128
• Description: Microcontroller unit (MCU)
• Manufacturer: MOTOROLA [Motorola, Inc]

A.2 ATD Characteristics
This section describes the characteristics of the analog to digital converter.
A.2.1 ATD Operating Characteristics
The
The following constraints exist to obtain full-scale, full range results:
V
beyond the power supply levels that it ties to. If the input level goes outside of this range it will effectively
be clipped.
A.2.2 Factors Influencing accuracy
Three factors — source resistance, source capacitance and current injection — have an influence on the
accuracy of the ATD.
A.2.2.1 Source Resistance
Due to the input pin leakage current as specified in
there will be a voltage drop from the signal source to the ATD input. The maximum source resistance R
Conditions are shown in
Num C
NOTES:
1. Full accuracy is not guaranteed when differential voltage is less than 4.50V
2. The minimum time assumes a final sample period of 2 ATD clocks cycles while the maximum time assumes a final sample
SSA
1
2
3
4
5
6
7
8
period of 16 ATD clocks.
Table A-8
D
C Differential Reference Voltage
D ATD Clock Frequency
D
D
D Stop Recovery Time (V
P Reference Supply current (Both ATD blocks on)
P Reference Supply current (Only one ATD block on)
V
Reference Potential
ATD 10-Bit Conversion Period
ATD 8-Bit Conversion Period
RL
V
shows conditions under which the ATD operates.
IN
Conv, Time at 2.0MHz ATD Clock f
Conv, Time at 2.0MHz ATD Clock f
Table A-4
V
RH
Rating
Table A-8 ATD Operating Characteristics
V
DDA
unless otherwise noted
DDA
=5.0 Volts)
(1)
This constraint exists since the sample buffer amplifier can not drive
Clock Cycles
Clock Cycles
ATDCLK
ATDCLK
High
Low
(2)
(2)
Table A-6
V
N
T
Symbol
N
f
T
ATDCLK
RH
CONV10
CONV10
CONV8
CONV8
V
I
I
V
t
REF
REF
SR
RH
–V
RL
RL
in conjunction with the source resistance
V
V
DDA
4.50
Min
0.5
MC9S12A128 Device Guide — V01.01
14
12
—
—
—
SSA
7
6
/2
5.00
Typ
—
—
—
—
—
—
—
—
V
0.750
0.375
V
Max
5.25
DDA
2.0
28
14
26
13
20
DDA
/2
Cycles
Cycles
MHz
Unit
mA
mA
V
V
V
s
s
s
66
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