Power Supply Options; Power Supply Considerations; Figure 6. Power Supply Options - Renesas RA4 Series User Manual

Renesas RA Family

5.1.1 Power Supply Options

This section describes the different ways in which FPB-RA4E1 board can be powered.
The MCU can be operated at a lower voltage than 3.3 V by removing the current measurement resistor and
powering the MCU via TP2.
Note: Other changes to the circuit where interfaces or pull-up resistors are used may also need to be
removed. Please review the schematic carefully before making these changes.
5.1.1.1 Option 1: Debug USB
5 V may be supplied from an external USB host to the USB debug connector (J9). Power from this source is
connected to the main system 5 V power. Reverse current protection is provided between this connector and
the main system 5 V power.
5.1.1.2 Option 2: Header Connector CN2
5 V may be supplied from an external power supply to connector CN2 (not fitted). CN2 is a standard 2-pin
header on a 0.1" (2.54 mm) pitch. Pin 1 is GND, and pin 2 is +5 V. Power from this source is connected to
the main system 5 V power. Reverse current protection is provided between CN2 and the main system 5 V
power.

5.1.2 Power Supply Considerations

The on-board LDO regulator which supplies +3.3 V has a built-in current limit of 2.0 A. Make sure the total
current required by the RA MCU, any active on-board features, and any connected peripheral devices does
not exceed this limit.
Note: The total current available from a typical USB host is 100 mA before enumeration, and 500 mA
maximum. Depending on the configuration of the kit, multiple power sources may be required.
R20UT4958EG0100 Rev 1.00
Sep.07.21

Figure 6. Power Supply Options

FPB-RA4E1 v1 – User's Manual
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