K40P81M100SF2_11 Datasheet, PDF (33/63 Pages) Freescale Semiconductor, Inc – Up to 100 MHz ARM Cortex-M4 core with DSP instructions delivering 1.25 Dhrystone MIPS per MHz

Peripheral operating requirements and behaviors
Table 23. 16-bit ADC operating conditions (continued)
Symbol
C_rate
Description
ADC conversion
rate
Conditions
16 bit modes
No ADC hardware
averaging
Continuous
conversions enabled
Peripheral clock =
50MHz
Min.
37.037
Typ.¹
Max.
Unit
—
361.402
Ksps
Notes
7
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. In order to use the maximum ADC conversion clock frequency ADHSC bit should be set and the ADLPC should be clear.
5. In order to use the maximum ADC conversion clock frequency ADHSC bit should be set and the ADLPC should be clear.
6. For guidelines and examples of conversion rate calculation please download the ADC calculator tool http://
cache.freescale.com/files/soft_dev_tools/software/app_software/converters/ADC_CALCULATOR_CNV.zip?fpsp=1
7. For guidelines and examples of conversion rate calculation please download the ADC calculator tool http://
cache.freescale.com/files/soft_dev_tools/software/app_software/converters/ADC_CALCULATOR_CNV.zip?fpsp=1
Z_AS
R_AS
SIMPLIFIED
INPUT PIN EQUIVALENT
CIRCUIT
Pad
leakage
due to
input
protection
Z_ADIN
SIMPLIFIED
CHANNEL SELECT
CIRCUIT
R_ADIN
ADC SAR
ENGINE
V_ADIN
V_AS
C_AS
INPUT PIN
INPUT PIN
INPUT PIN
R_ADIN
R_ADIN
R_ADIN
C_ADIN
Figure 10. ADC input impedance equivalency diagram
K40 Sub-Family Data Sheet Data Sheet, Rev. 4, 3/2011.
Freescale Semiconductor, Inc.
Preliminary
33