MC9S12B128_05 Datasheet, PDF (93/132 Pages) Motorola, Inc – Covers also preliminary MC9S12B64 using MC9S12B128 die

A.2 ATD Characteristics
Device User Guide —9S12B128DGV1/D V01.13
This section describes the characteristics of the analog to digital converter.
The ATD is specified and tested for both the 3.3V and 5V range. For ranges between 3.3V and 5V the
ATD accuracy is generally the same as in the 3.3V range but is not tested in this range in production test.
A.2.1 ATD Operating Characteristics In 5V Range
The Table A-10 shows conditions under which the ATD operates.
The following constraints exist to obtain full-scale, full range results:
V_SSA ≤ V_RL ≤ V_IN ≤ V_RH ≤ V_DDA. This constraint exists since the sample buffer amplifier can not drive
beyond the power supply levels that it ties to. If the input level goes outside of this range it will effectively
be clipped.
Table A-10 ATD Operating Characteristics In 5V Range
Conditions are shown in Table A-4 unless otherwise noted. Supply Voltage 5V-10% <= V_DDA <=5V+10%
Num C
Rating
Symbol Min
Typ
Max
Unit
Reference Potential
1D
Low
High
V_RL
V_RH
V_SSA
V_DDA/2
V_DDA/2
V
V_DDA
V
2 C _{Differential Reference Voltage}¹
V_RH-V_RL
4.75
5.00
5.25
V
3 D ATD Clock Frequency
f_ATDCLK
0.5
2.0
MHz
ATD 10-Bit Conversion Period
4D
Clock Cycles² N_CONV10
14
Conv, Time at 2.0MHz ATD Clock f_ATDCLK T_CONV10
7
28 Cycles
14
µs
ATD 8-Bit Conversion Period
5D
Clock Cycles² N_CONV8
12
Conv, Time at 2.0MHz ATD Clock f_ATDCLK T_CONV8
6
26 Cycles
13
µs
6 D Recovery Time (V_DDA=5.0 Volts)
t_REC
20
µs
7 P Reference Supply current
I_REF
0.375 mA
NOTES:
1. Full accuracy is not guaranteed when differential voltage is less than 4.75V
2. The minimum time assumes a final sample period of 2 ATD clocks cycles while the maximum time assumes a final sample
period of 16 ATD clocks.
A.2.2 ATD Operating Characteristics In 3.3V Range
The Table A-11 shows conditions under which the ATD operates.
The following constraints exist to obtain full-scale, full range results:
V_SSA ≤ V_RL ≤ V_IN ≤ V_RH ≤ V_DDA. This constraint exists since the sample buffer amplifier can not drive
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