AN4325 datasheet(7/27 Pages) STMICROELECTRONICS

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AN4325

Power supplies and reset sources of the STM32F030 family

1.1.1

Independent analog converter supply

To improve conversion accuracy and to extend the supply flexibility, the analog domain 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 VDDA pin.



An isolated supply ground connection is provided on pin VSSA.

The VDDA supply can be equal to or higher than VDD. This allows VDD to stay low while still

providing the full performance for the analog blocks.

When a single supply is used, VDDA must be externally connected to VDD. It is

recommended to use an external filtering circuit in order to ensure a noise free VDDA.

When VDDA is different from VDD, VDDA must be always higher or equal to VDD. To keep

safe potential difference between VDDA and VDD during power-up/power-down, an external

Schottky diode may be used between VDD and VDDA. Refer to the datasheet for the

maximum allowed difference.

Figure 2. Schottky diode connection

AN4325 Datasheet(PDF) 7 Page - STMicroelectronics