Datasheet


NOTE
The RP2040 has an on-chip linear regulator (LDO) that powers the digital core at 1.1V (nominal) from the 3.3V
supply, which is not shown in Figure 6.
3.5. Powering Raspberry Pi Pico W
The simplest way to power Pico W is to plug in the micro-USB, which will power VSYS (and therefore the system) from
the 5V USB VBUS voltage, via D1 (so VSYS becomes VBUS minus the Schottky diode drop).
If the USB port is the only power source, VSYS and VBUS can be safely shorted together to eliminate the Schottky diode
drop (which improves efficiency and reduces ripple on VSYS).
If the USB port is not going to be used, it is safe to power Pico W by connecting VSYS to your preferred power source (in
the range ~1.8V to 5.5V).

IMPORTANT
If you are using Pico W in USB host mode (e.g. using one of the TinyUSB host examples) then you must power Pico
W by providing 5V to the VBUS pin.
The simplest way to safely add a second power source to Pico W is to feed it into VSYS via another Schottky diode (see
Figure 7). This will 'OR' the two voltages, allowing the higher of either the external voltage or VBUS to power VSYS, with
the diodes preventing either supply from back-powering the other. For example a single Lithium-Ion cell* (cell voltage
~3.0V to 4.2V) will work well, as will three AA series cells (~3.0V to ~4.8V) and any other fixed supply in the range
~2.3V to 5.5V. The downside of this approach is that the second power supply will suffer a diode drop in the same way
as VBUS does, and this may not be desirable from an efficiency perspective or if the source is already close to the lower
range of input voltage allowed for the RT6154.
VBUS VSYS
W L_GPIO 2
R2
100 K
1%
M0 60 3
50 mW
C1
47u
6.3V
20 %
M2012
X5R
R10
10K
1%
M0 60 3
50 mW
D1
MBR120VLS FT1G
2 1
R1
10K
1%
M0 60 3
50 mW
3V3_E N
V
D
Feed VSYS pin f rom
external supply (V) via
Schotty diode (D)
Figure 7. Pico W
power ORing using
diodes.
An improved way to power from a second source is using a P-channel MOSFET (P-FET) to replace the Schottky diode as
shown in Figure 8. Here, the gate of the FET is controlled by VBUS, and will disconnect the secondary source when
VBUS is present. The P-FET should be chosen to have low on resistance, and therefore overcomes the efficiency and
Raspberry Pi Pico W Datasheet
3.5. Powering Raspberry Pi Pico W 13