Hardware description
Figure 7: Power supply options (board back)
5.3.1 5 V power sources
The nRF5340 PDK board has a 5 V boost regulator.
It gives a stable 5 V output from four possible sources:
• USB connector J2 for the interface MCU
• Li-Po polymer battery connectors (J6 or P27)
• VIN 3–5 V pin on P20
Each of these sources has a reverse protection diode to prevent current flowing in the wrong direction if
multiple sources are connected at the same time.
Figure 8: 5 V regulator and protecting diodes
5.3.2 VDD power sources
The main board supply (VDD) can be sourced from the 5 V domain, external power supply, and coin cell
battery.
For the 5 V domain, there are two regulators, one fixed 3 V buck regulator and one voltage follower
regulator that follows the VDD_nRF voltage. The coin cell battery and external power supply are not
regulated.
• 5 V domain:
• Fixed 3 V buck regulator
• VDD_nRF voltage follower
• External power supply
• Coin cell battery
For more information about power sources, see nRF5340 power source on page 17.
The power sources are routed through a set of load switches, which is controlled by logic to give the
correct priority of the power sources.
If the high voltage regulator of the nRF5340 is used, the board will be supplied from the VDD_nRF voltage
follower regardless of the state of the other power sources.
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