NXP Semiconductors K32 L2A Series, Reference Manual, Page: 221 / 1379

11.6 Application information
The ADC has been designed to be integrated into a microcontroller for use in embedded
control applications requiring an ADC.
For guidance on selecting optimum external component values and converter parameters
see
AN4373: Cookbook for SAR ADC Measurements .
11.6.1 External pins and routing
11.6.1.1 Analog supply pins
Depending on the device, the analog power and ground supplies, V
DDA
and V
SSA
, of the
ADC module are available as:
• V
DDA
and V
SSA
available as separate pins—When available on a separate pin, both
V
DDA
and V
SSA
must be connected to the same voltage potential as their
corresponding MCU digital supply, V
DD
and V
SS
, and must be routed carefully for
maximum noise immunity and bypass capacitors placed as near as possible to the
package.
• V
SSA
is shared on the same pin as the MCU digital V
SS
.
• V
SSA
and V
DDA
are shared with the MCU digital supply pins—In these cases, there
are separate pads for the analog supplies bonded to the same pin as the corresponding
digital supply so that some degree of isolation between the supplies is maintained.
If separate power supplies are used for analog and digital power, the ground connection
between these supplies must be at the V
SSA
pin. This must be the only ground connection
between these supplies, if possible. V
SSA
makes a good single point ground location.
11.6.1.2 Analog voltage reference pins
In addition to the analog supplies, the ADC module has connections for two reference
voltage inputs used by the converter:
• V
REFSH
is the high reference voltage for the converter.
• V
REFSL
is the low reference voltage for the converter.
The ADC can be configured to accept one of two voltage reference pairs for V
REFSH
and
V
REFSL
. Each pair contains a positive reference and a ground reference. The two pairs are
external, V
REFH
and V
REFL
and alternate, V
ALTH
and V
ALTL
. These voltage references are
Chapter 11 Analog-to-Digital Converter (ADC)
K32 L2A Reference Manual, Rev. 2, 01/2020
NXP Semiconductors 221