MC9S12K Datasheet, PDF (99/126 Pages) Freescale Semiconductor, Inc – Microcontrollers

Device User Guide — 9S12KT256DGV1/D V01.09
1. A current is injected into the channel being converted. The channel being stressed has conversion
values of $3FF ($FF in 8-bit mode) for analog inputs greater than VRH and $000 for values less
than VRL unless the current is higher than specified as disruptive conditions.
2. Current is injected into pins in the neighborhood of the channel being converted. A portion of this
current is picked up by the channel (coupling ratio K), This additional current impacts the accuracy
of the conversion depending on the source resistance.
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.
Table A-13 ATD Electrical Characteristics
Conditions are shown in Table A-4 unless otherwise noted
Num
Rating
Symbol
Min
Typ
Max Unit
1 Max input Source Resistance
R_S
-
-
1
KΩ
Total Input Capacitance
2 Non Sampling
Sampling
C_INN
C_INS
10
pF
22
3 Disruptive Analog Input Current
I_NA
-2.5
2.5
mA
4 Coupling Ratio positive current injection
K_p
10^-4
A/A
5 Coupling Ratio negative current injection
K_n
10^-2
A/A
A.5.3 ATD accuracy
Table A-14 and Table A-15 specify the ATD conversion performance excluding any errors due to
current injection, input capacitance and source resistance.
Table A-14 5V ATD Conversion Performance
Conditions are shown in Table A-4 unless otherwise noted
V_REF = V_RH - V_RL = 5.12V. Resulting to one 8 bit count = 20mV and one 10 bit count = 5mV
f_ATDCLK = 2.0MHz
Num C
Rating
Symbol
Min
Typ
1 P 10-Bit Resolution
LSB
5
2 P 10-Bit Differential Nonlinearity
DNL
–1
3 P 10-Bit Integral Nonlinearity
INL
–2.5
±1.5
4 P _{10-Bit Absolute Error}¹
AE
-3
±2.0
5 C 10-Bit Absolute Error at f_ATDCLK= 4MHz
AE
±7.0
6 P 8-Bit Resolution
LSB
20
7 P 8-Bit Differential Nonlinearity
DNL
–0.5
8 P 8-Bit Integral Nonlinearity
INL
–1.0
±0.5
9 P _{8-Bit Absolute Error}⁽¹⁾
AE
-1.5
±1.0
Max
1
2.5
3
0.5
1.0
1.5
Unit
mV
Counts
Counts
Counts
Counts
mV
Counts
Counts
Counts
Freescale Semiconductor
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