Product Info

ABLUE TECHNOLOGY
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8
Reference Circuit configuration 3
Configurations summary for reference circuit 3
Config no.
Main Supply
EXT Supply Output
USB
VDDH
VDD
Config.3
N/A
Battery/Ext.regulator
No
No
Explanation of symbols in reference circuit 3 schematic
Symbol
Parameter
Min.
Typ.
Max.
Units
V
DD
Main supply voltage in normal voltage mode
1.7
3
3.6
V
Some general guidance is summarized here:
 Main supply voltage is connected to VDD/VDDH. The system will enter one of two supply voltage modes,
normal or high voltage mode, depending on how the supply voltage is connected to these pins. Normal
voltage mode is entered when the supply voltage is connected to both the VDD and VDDH pins (so that
VDD equals VDDH).High voltage mode is entered when the supply voltage is only connected to the
VDDH pin and the VDD pin is not connected to any voltage supply.
 By default, the LDO regulators in the chip are enabled and the DC/DC regulator of REG1 stage is disabled.
Register DCDCEN is used to enable the DC/DC regulator for REG1 stage. External LC filters has been
connected in the Module for DC/DC regulators being used.
 The GPIO high reference voltage always equals the level on the VDD pin. In normal voltage mode, the
GPIO high level equals the voltage supplied to the VDD pin, and in high voltage mode it equals the level
specified in the register REGOUT0 UICR registers.
 When the power is supplied to VDDH, the output from the VDD pin could be used to supply external
circuitry. The feature must be configured in the EXTSUPLLY and REGOUT0 UICR registers. In the
reference circuitry, External supply is annotated with the VEXT net name.
 When using the USB peripheral, a 5V USB supply needs to be provided on the VBUS pin.