Independent A/D Converter Supply And Reference Voltage; Figure 10. Power Supply Overview For Stm32F42Xxx And Stm32F43Xxx - ST STM32F405 Reference Manual

RM0090

Figure 10. Power supply overview for STM32F42xxx and STM32F43xxx

VBAT =
1.65 to 3.6V
2 × 2.2 μF
V
DD
19 × 100 nF
+ 1 × 4.7 μF
BYPASS_REG
V DD
V REF
100 nF
100 nF
+ 1 μF
+ 1 μF
1. V and V must be connected to V
DDA SSA
5.1.1

Independent A/D converter supply and reference voltage

To improve conversion accuracy, the ADC has an independent power supply which can be
separately filtered and shielded from noise on the PCB.
•
The ADC voltage supply input is available on a separate V
•
An isolated supply ground connection is provided on pin V
To ensure a better accuracy of low voltage inputs, the user can connect a separate external
reference voltage ADC input on V
V BAT
GP I/Os
V
CAP_1
V
CAP_2
V
DD Voltage
1/2/...14/20
regulator
V SS
1/2/...14/20
PDR_ON
V DDA
V REF+
V REF-
V SSA
and V , respectively.
DD SS
REF
RM0090 Rev 18
Po wer swi tch
OUT
IO
Logic
IN
Reset
controller
Analog:
ADC
RCs, PLL,
...
. The voltage on V
REF
Power controller (PWR)
Backup circuitry
(OSC32K,RTC,
Wakeup logic
Backup registers,
backup RAM)
Kernel logic
(CPU,
digital
& RAM)
Flash memory
pin.
DDA
.
SSA
ranges from 1.8 V to V
MS30482V2
.
DDA
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