Datasheet

Appendix A Electrical Characteristics
MC9S12XE-Family Reference Manual Rev. 1.25
Freescale Semiconductor 1221
The additional input voltage error on the converted channel can be calculated as:
V
ERR
= K * R
S
* I
INJ
with I
INJ
being the sum of the currents injected into the two pins adjacent to the converted channel.
A.2.3 ATD Accuracy
Table A-17 and Table A-18 specify the ATD conversion performance excluding any errors due to current
injection, input capacitance and source resistance.
A.2.3.1 ATD Accuracy Definitions
For the following definitions see also Figure A-1.
Differential non-linearity (DNL) is defined as the difference between two adjacent switching steps.
The integral non-linearity (INL) is defined as the sum of all DNLs:
Table A-16. ATD Electrical Characteristics
Conditions are shown in Table A-4 unless otherwise noted
Num C Rating Symbol Min Typ Max Unit
1 C Max input source resistance
(1)
1. Refer to A.2.2.3 for further information concerning source resistance
R
S
—— 1KΩ
2 D Total input capacitance Non sampling
Total input capacitance Sampling
C
INN
C
INS
—
—
—
—
10
16
pF
3 D Input internal Resistance
R
INA
—
515kΩ
4 C Disruptive analog input current I
NA
–2.5 — 2.5 mA
5 C Coupling ratio positive current injection K
p
— — 1E-4 A/A
6 C Coupling ratio negative current injection K
n
— — 2E-3 A/A
DNL i()
V
i
V
i1–
–
1LSB
--------------------------
1–=
INL n() DNL i()
i1=
n
∑
V
n
V
0
–
1LSB
---------------------
n–==