Document:
SHARKY - User’s Guide
2020/11/18
Doc: UG_MDX-STWBx, Rev 1.7
pag. 20 of 38
5. Usage
This chapter describes how to connect, configure and interact with the Sharky and Sharky Pro
modules.
5.1. Power Supply
Sharky and Sharky PRO modules are powered by:
●
VCC/VDD pins, from 1.71 V to 3.6 V
●
VDDA pin, from 1.62 V (ADCs/COMPs) to 2.4 V (VREFBUF) to 3.6 V .
VDDA is the external analog power supply for A/D converters, D/A converters, voltage
reference buffer, operational amplifiers and comparators. The VDDA voltage level is
independent from the VDD voltage and should preferably be connected to VDD when
these peripherals are not used.
●
VDDUSB = 3.0 V to 3.6 V
VDDUSB is the external independent power supply for USB transceivers. The
VDDUSB voltage level is independent from the VDD voltage and should preferably be
connected to VDD when the USB is not used.
●
VBAT = 1.55 V to 3.6 V
VBAT is the power supply for RTC, external clock 32 kHz oscillator and backup
registers (through power switch) when VDD is not present.
During power up and power down, the following power sequence is required:
●
When VDD < 1 V, the other power supplies (VDDA , VDDUSB and V LCD ) must
remain below VDD + 0.3 V. During the power down VDD can temporarily become lower
than the other supplies only if the energy provided to the MCU remains below 1 mJ.
This allows the external decoupling capacitors to discharge with different time
constants.
●
When VDD ≥ 1 V, all power supplies become independent.
An embedded linear voltage regulator is used to supply the internal digital power VCORE .
VCORE is the power supply for digital peripherals, SRAM1 and SRAM2. The Flash memory
is supplied by VCORE and VDD .
