Datasheet

Appendix A Electrical Characteristics
MC9S12E128 Data Sheet, Rev. 1.07
Freescale Semiconductor 589
A.6 ATD Characteristics
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.6.1 ATD Operating Characteristics — 5V Range
The Table A-19 shows conditions under which the ATD operates.
The following constraints exist to obtain full-scale, full range results:
VSSA ≤ VRL ≤ VIN ≤ VRH ≤ VDDA. 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-19. 5V ATD Operating Characteristics
Conditions are shown in Table A-4 unless otherwise noted. Supply Voltage 5V-10% <= VDDA <=5V+10%
Num C Rating Symbol Min Typ Max Unit
1 D Reference Potential
Low
High
V
RL
V
RH
V
SSA
V
DDA/2
—
—
V
DDA/2
V
DDA
V
V
2 C Differential Reference Voltage
1
1
Full accuracy is not guaranteed when differential voltage is less than 4.75V
V
RH
–V
RL
4.75 5.0 5.25 V
3 D ATD Clock Frequency f
ATDCLK
0.5 — 2.0 MHz
4DATD 10-Bit Conversion Period
Clock Cycles
2
Conv, Time at 2.0MHz ATD Clock f
ATDCLK
Conv, Time at 4.0MHz
3
ATD Clock f
ATDCLK
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.
3
Reduced accuracy see Table A-22 and Table A-23.
N
CONV10
T
CONV10
T
CONV10
14
7
3.5
—
—
—
28
14
7
Cycles
µs
µs
5 D ATD 8-Bit Conversion Period
Clock Cycles
1
Conv, Time at 2.0MHz ATD Clock f
ATDCLK
N
CONV8
T
CONV8
12
6
—
—
26
13
Cycles
µs
6 D Stop Recovery Time (V
DDA
= 5.0 Volts) t
SR
——20µs
7 P Reference Supply current I
REF
— — 0.375 mA