Power Supply; Digital Power Supply - Espressif Systems ESP32-S2 Hardware Design Manuallines

2. Schematic Checklist
• Touch Sensor

2.1 Power Supply

4
For further details of using the power supply pins, please refer to Section Power Scheme in

2.1.1 Digital Power Supply

Pin27 and pin45 are the power supply pins for RTC IO and CPU IO, in a voltage range of 3.0 V
3.6 V, respectively. We recommend adding extra 0.1 µF capacitors close to each digital power supply pin.
VDD_SPI can work as the power supply for the external device at either 1.8 V (when GPIO45 is 1 during boot),
or 3.3 V (when GPIO45 is 0 and at default state during boot). We recommend adding extra 0.1 µF and 1 µF
capacitors close to VDD_SPI.
• When VDD_SPI operates at 1.8 V, it can be generated from ESP32-S2's internal LDO. The maximum current
this LDO can offer is 40 mA, and the output voltage range is 1.8 V
• When VDD_SPI operates at 3.3 V, it is driven directly by VDD3P3_RTC_IO through a 5 Ω resistor, therefore,
there will be some voltage drop from VDD3P3_RTC_IO.
VDD_SPI can also be driven by an external power supply.
The schematic for ESP32-S2 digital power supply pins is shown in Figure 2.
GND
1
VDDA
2
LNA_IN
3
VDD3P3
4
VDD3P3
GPIO0 5
GPIO0
6
GPIO1
GPIO1
GPIO2 7
GPIO2
GPIO3 8
GPIO3
GPIO4 9
GPIO4
GPIO5 10
GPIO5
11
GPIO6
GPIO6
GPIO7 12
GPIO7
GPIO8 13
GPIO8
GPIO9 14
GPIO9
U1
VDD33
C15
0.1uF
GND
4
Notice:
When using VDD_SPI as the power supply pin for the external 3.3 V flash/PSRAM, the supply voltage should be
3.0 V or above, so as to meet the requirements of flash/PSRAM's working voltage.
Espressif Systems
3
GND
GND GND
Y1
C1
TBD
GND
R4
0 40MHz (±10ppm)
VDD_SPI
ESP32-S2
R11
GND
Figure 2: ESP32­S2 Digital Power Supply Pins
3
Submit Documentation Feedback
C4
TBD
R3 499
C10
0.1uF
GND
42
GPIO38
41
GPIO37
40
GPIO36
39
GPIO35
38
GPIO34
37
GPIO33
36 R13 0
SPID
35 R14 0
SPIQ
34
R10 0
SPICLK
33
SPICS0
32
R15 0
SPIWP
31 R16 0
SPIHD
30
29 GPIO26
SPICS1
C13 C14
0.1uF 1uF
GND GND
10K
C16
0.1uF
3 ESP32-S2 Hardware Design Guidelines V1.1
2
ESP32-S2
~ 3.6 V and 2.8 V
~ 3.6 V.
CHIP_PU
GPIO46
GPIO45
U0RXD
U0TXD
GPIO42
GPIO41
GPIO40
GPIO39
VDD33
R8
10K(NC)
GPIO38
GPIO37
GPIO36 SPICS0
GPIO35
GPIO34 SPICLK
GPIO33
SPID SPIHD
SPIQ
SPICLK
SPICS0
SPIWP
SPIHD
NC: No component.
SPICS1
VDD_SPI
R9
10K(NC)
SPICS1
VDD33
SPICLK
SPIHD
2
1
Datasheet.
~
VDD_SPI
U2
1 5
/CS DI
6 2
CLK DO
7 3
/HOLD /WP
FLASH-3V3
GND
VDD_SPI
U3
1 5
CS SI/SIO0
6 2
SCLK SO/SIO1
7 3
SIO3 SIO2
(Optio
PSRAM-3V3
GND
1
SPID
SPIQ
SPIW
SPID
SPIQ
SPIW