MC9S12T64 Datasheet, PDF (570/608 Pages) Motorola, Inc – Specification

Freescale Semiconductor, Inc.
Electrical Characteristics
Source
Resistance:
Source
Capacitance
Due to the input pin leakage current as specified in Table 108 in
conjunction with the source resistance there will be a voltage drop from
the signal source to the ATD input. The maximum source resistance R_S
specifies results in an error of less than 1/2 LSB (2.5mV) at the maximum
leakage current. If device or operating conditions are less than worst
case or leakage-induced error is acceptable, larger values of source
resistance is allowed.
When sampling an additional internal capacitor is switched to the input.
This can cause a voltage drop due to charge sharing with the external
and the pin capacitance. For a maximum sampling error of the input
voltage ≤ 1LSB, then the external filter capacitor, C_f ≥ 1024 * (C_INS–
C_INN).
Table 111 ATD Electrical Characteristics
Conditions are shown in Table 106 unless otherwise noted
Num
Rating
Symbol Min
Typ
1 Max input Source Resistance
R_S
—
—
Total Input Capacitance
2
Non Sampling
Sampling
C_INN
C_INS
3 Disruptive Analog Input Current
I_NA
–2.5
Max Unit
1
KΩ
10
pF
15
2.5
mA
ATD accuracy
Table 112 specifies the ATD conversion performance excluding any
errors due to current injection, input capacitance and source resistance.
MC9S12T64Revision 1.1.1
Electrical Characteristics
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