Information

Table 23. 16-bit ADC operating conditions (continued)
Symbol Description Conditions Min.
Typ.
1
Max. Unit Notes
C
rate
ADC conversion
rate
16 bit modes
No ADC hardware
averaging
Continuous
conversions enabled,
subsequent conversion
time
37.037 — 461.467 Ksps
5
1. Typical values assume V
DDA
= 3.0 V, Temp = 25°C, f
ADCK
= 1.0 MHz unless otherwise stated. Typical values are for
reference only and are not tested in production.
2. DC potential difference.
3. This resistance is external to MCU. The analog source resistance should be kept as low as possible in order to achieve the
best results. The results in this datasheet were derived from a system which has <8 Ω analog source resistance. The R
AS
/
C
AS
time constant should be kept to <1ns.
4. To use the maximum ADC conversion clock frequency, the ADHSC bit should be set and the ADLPC bit should be clear.
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
R
AS
V
AS
C
AS
Z
AS
V
ADIN
Z
ADIN
R
ADIN
R
ADIN
R
ADIN
R
ADIN
C
ADIN
Pad
leakage
due to
input
protection
INPUT PININPUT PIN
INPUT PIN
INPUT PIN
SIMPLIFIED
INPUT PIN EQUIVALENT
CIRCUIT
SIMPLIFIED
CHANNEL SELECT
CIRCUIT
ADC SAR
ENGINE
Figure 10. ADC input impedance equivalency diagram
6.6.1.2 16-bit ADC electrical characteristics
Table 24. 16-bit ADC characteristics (V
REFH
= V
DDA
, V
REFL
= V
SSA
)
Symbol Description
Conditions
1
Min.
Typ.
2
Max. Unit Notes
I
DDA_ADC
Supply current 0.215 — 1.7 mA 3
Table continues on the next page...
Peripheral operating requirements and behaviors
K20 Sub-Family Data Sheet, Rev. 4 5/2012.
Freescale Semiconductor, Inc. 37