Analog
5. For guidelines and examples of conversion rate calculation, download the ADC calculator tool: http://cache.freescale.com/
files/soft_dev_tools/software/app_software/converters/ADC_CALCULATOR_CNV.zip?fpsp=1
SIMPLIFIED
INPUT PIN EQUIVALENT
ZADIN
CIRCUIT
SIMPLIFIED
CHANNEL SELECT
CIRCUIT
Pad
leakage
due to
input
protection
ZAS
ADC SAR
ENGINE
RAS
RADIN
VADIN
CAS
VAS
RADIN
RADIN
RADIN
INPUT PIN
INPUT PIN
INPUT PIN
CADIN
Figure 9. ADC input impedance equivalency diagram
6.6.1.2 12-bit ADC electrical characteristics
Table 23. 12-bit ADC characteristics (VREFH = VDDA, VREFL = VSSA
)
Conditions1
Typ.2
Symbol Description
Min.
Max.
Unit
Notes
IDDA_ADC Supply current
0.215
—
1.7
mA
3
ADC
asynchronous
clock source
• ADLPC=1, ADHSC=0
1.2
3.0
2.4
4.4
2.4
4.0
5.2
6.2
3.9
7.3
6.1
9.5
tADACK = 1/
fADACK
MHz
MHz
MHz
MHz
• ADLPC=1, ADHSC=1
• ADLPC=0, ADHSC=0
• ADLPC=0, ADHSC=1
fADACK
Sample Time
See Reference Manual chapter for sample times
LSB4
LSB4
TUE
DNL
Total unadjusted
error
• 12 bit modes
• <12 bit modes
—
—
4
6.8
2.1
5
5
1.4
Differential non-
linearity
• 12 bit modes
—
0.7
-1.1 to
+1.9
-0.3 to 0.5
• <12 bit modes
• 12 bit modes
—
—
0.2
1.0
LSB4
INL
Integral non-
linearity
-2.7 to
+1.9
5
-0.7 to
+0.5
• <12 bit modes
—
0.5
Table continues on the next page...
MCF51JU128 Data Sheet, Rev. 4, 01/2012.
Freescale Semiconductor, Inc.
37
FREESCALE [ Freescale ]
