Schematic Checklist And Pcb Layout Design; Schematic Checklist; Esp32 Schematics - Espressif Systems ESP32 Hardware Design Manuallines

2. SCHEMATIC CHECKLIST AND PCB LAYOUT DESIGN

2. Schematic Checklist and PCB Layout Design
ESP32's integrated circuitry requires only 20 resistors, capacitors and inductors, one crystal and one SPI flash
memory chip. ESP32 integrates the complete transmit/receive RF functionality including the antenna switches, RF
balun, power amplifier, low noise receive amplifier, filters, power management module, and advanced calibration
circuitries.
ESP32's high integration allows for simple peripheral circuit design. This document details ESP32 schematics and
PCB layout design.
While the high level of integration makes the PCB design and layout process simple, the performance of the system
strongly depends on system design aspects. To achieve the best overall system performance, please follow the
guidelines specified in this document for circuit design and PCB layout. All the common rules associated with
good PCB design still apply and this document is not an exhaustive list of good design practices.

2.1 Schematic Checklist

ESP32 schematics is as shown in Figure 1.
VDD33
VDD33
VDD33
L5
C13 C12 C11
C10
10uF NC 1uF 0.1uF
GND GND GND GND
ANT1
1 L4 2.7nH±0.1nH
2
C15 C14
C16
PCB ANT
270pF(NC)
C17
GND GND GND
270pF(NC)
VDD33
R4
10K
CHIP_PU
C22
0.1uF
GND
Any basic ESP32 circuit design may be broken down into seven major sections:
• Power supply
• Power-on sequence and system reset
• Flash
Espressif Systems
C1
22pF
C20
C3 GND
20K
R1
100pF
1uF
C5
C6 3.3nF
GND
GND
10nF
C9
GND
0.1uF
GND
2.0nH
C21
NC
GND
1
VDDA
2
LNA_IN
3
VDD3P3
4
VDD3P3
SENSOR_VP 5
SENSOR_VP
6
SENSOR_CAPP
7
SENSOR_CAPN
SENSOR_VN 8
SENSOR_VN
CHIP_PU 9
CHIP_PU
GPIO34 10
VDET_1
GPIO35 11
VDET_2
GPIO32 12
32K_XP
GPIO33 13
32K_XN
GPIO25 14
GPIO25
U2
Figure 1: ESP32 Schematics
GND
U1
GND GND
C2
22pF
GND
40MHz+/-10ppm
R3 499R
GND
C4
0.1uF
38
GPIO19
37
VDD3P3_CPU
36
GPIO23
35
GPIO18
34
GPIO5
33
SD_DATA_1
32
SD_DATA_0
31
SD_CLK
30
SD_CMD
29
SD_DATA_3
28
SD_DATA_2
27
GPIO17
26
VDD_SDIO
25
GPIO16
C18
1uF
ESP32
GND
C19
0.1uF
GND
7 ESP32 Hardware Design Guidelines V2.1
GPIO21
U0TXD
U0RXD
GPIO22
VDD33
VDD_SDIO
GPIO19
GPIO23
GPIO18
GPIO5
1
SDI/SD1 SCS/CMD
/CS DI
SDO/SD0
SCK/CLK SCK/CLK 6
CLK DO
SCS/CMD
SWP/SD3 SHD/SD2 7
/HOLD /WP
SHD/SD2
GPIO17 U3 FLASH
GPIO16
GND
VDD_SDIO
VDD33
5
SDI/SD1
2 SDO/SD0
3 SWP/SD3