NXP Semiconductors Kinetis KE1xZ256, Reference Manual

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Table 36-4. ADC input signal descriptions
Signal Description
AD n Single-Ended Analog Channel Inputs
V
REFSH
Voltage Reference Select High
V
REFSL
Voltage Reference Select Low
V
DDA
Analog Power Supply
V
SSA
Analog Ground
36.3.1 Analog Power (V
DDA
)
The ADC analog portion uses V
DDA
as its power connection. In some packages, V
DDA
is
connected internally to V
DD
. If externally available, connect the V
DDA
pin to the same
voltage potential as V
DD
. External filtering may be necessary to ensure clean V
DDA
for
good results.
36.3.2 Analog Ground (V
SSA
)
The ADC analog portion uses V
SSA
as its ground connection. In some packages, V
SSA
is
connected internally to V
SS
. If externally available, connect the V
SSA
pin to the same
voltage potential as V
SS
.
36.3.3 Voltage Reference Select
V
REFSH
and V
REFSL
are the high and low reference voltages for the ADC module.
The ADC can be configured to accept one of the voltage reference pairs for V
REFSH
and
V
REFSL
by configuring V
REFSH
as V
REFH
or
VALTH
. Each pair contains a positive
reference that must be between the minimum Ref Voltage High and V
DDA
, and a ground
reference that must be at the same potential as V
SSA
. The two pairs are external (V
REFH
and V
REFL
) alternate (V
ALTLH
and V
REFL
). These voltage references are selected using
SC2[REFSEL]. The alternate voltage reference, V
ALTH
may select additional external pin
or internal source depending on MCU configuration. See the chip configuration
information on the Voltage References specific to this MCU.
Chapter 36 Analog-to-Digital Converter (ADC)
Kinetis KE1xZ256 Sub-Family Reference Manual, Rev. 3, 07/2018
NXP Semiconductors 739