STMicroelectronics Nucleo Development Board for STM32 Microcontrollers NUCLEO-F103RB NUCLEO-F103RB Data Sheet

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DocID025833 Rev 5

          

          

VIN or E5V can be used as external power supply in case the current consumption of 
NUCLEO and extensions boards exceeds the allowed current on USB. In this condition it is 
still possible to use the USB for communication, for programming or debugging only, but it is 
mandatory to power supply the board first using VIN or E5V then connect the USB cable to 
the PC. Proceeding this way ensures that the enumeration occurs thanks to the external 
power source. 

The following power sequence procedure must be respected: 
1.

Connect the jumper between pin 2 and pin 3 of JP5. 

2.  Check that JP1 is removed.
3.  Connect the external power source to VIN or E5V.
4.  Power on the external power supply 7 V< VIN < 12 V to VIN, or 5 V for E5V.
5.  Check that LD3 is turned ON.
6.  Connect the PC to USB connector CN1.

If this order is not respected, the board may be supplied by VBUS first then by VIN or E5V, 
and the following risks may be encountered:

VIN

CN6 pin 8 

CN7 pin 24

7 V to 12 V

800 mA

From 7 V to 12 V only and input current capability 

is linked to input voltage:

800 mA input current when Vin=7 V

450 mA input current when 7 V<Vin (< or =) 9 V

250 mA input current when 9 V<Vin (< or =) 12 V

E5V

CN7 pin 6

4.75 V to 

5.25 V

500 mA

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JP5

U5V (ST-LINK VBUS) is used as power source when JP5 is set as shown below 

(Default setting)

VIN or E5V is used as power source when JP5 is set as shown below.







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