
GD32L23x User Manual
590
24.
VREF
24.1.
Overview
A precision internal reference circuit is inside. The precision internal reference is used to
provide reference voltage for ADC/DAC, or used by off-chip circuit connecting to V
REF
pin.
24.2.
Characteristics
The precision internal reference features are described as follows:
Stable voltage, and product trimmed
Connects to V
REF
pin to source off-chip circuits
Provides 2.5V reference voltage
24.3.
Function overview
The precision reference is enabled by set the VREFEN bit in VREF_CS register (the
SYSCFGEN bit in RCU_APB2EN register needs to be set to 1 before that), producing 2.5V
reference voltage and connecting to V
REF
pin. When VREFEN is disabled, off-chip reference
voltage could be injected to V
REF
pin to source ADC/DAC. If there is no V
REF
pin (refer to
datasheet), the V
REF
is connected to V
DDA
and the VREFEN bit must keep 0.
When using precision internal reference voltage, and a bypass capacitor about 1uF (or 1uF
and 10nF connected in parallel) which is recommended to ground is required.
Figure 24-1. Precision Reference Connection
Voltage
Reference
To External
Circuitry
V
REF
GND
2.5V
1uF/1uF+10nF
The internal reference voltage can be configured in four different modes depending on
VREFEN and HIPM bits configuration. These modes are provided in the table below: