1. Manuals
  2. Brands
  3. Espressif Systems Manuals
  4. Single board computers
  5. ESP32-S2
  6. Hardware design manuallines

Espressif Systems ESP32-S2 Hardware Design Manuallines

Hide thumbs Also See for ESP32-S2:
  • Faq (191 pages)
Table of Contents

Advertisement

Quick Links

Download this manual
ESP32­S2
Hardware Design Guidelines
www.espressif.com
Version 1.1
Espressif Systems
Copyright © 2020

Advertisement

Table of Contents
loading
Need help?

Need help?

Do you have a question about the ESP32-S2 and is the answer not in the manual?

Questions and answers

Related Manuals for Espressif Systems ESP32-S2

Summary of Contents for Espressif Systems ESP32-S2

  • Page 1 ESP32­S2 Hardware Design Guidelines Version 1.1 Espressif Systems Copyright © 2020 www.espressif.com...
  • Page 2 About This Document The guidelines outline recommended design practices when developing standalone or add-on systems based on the ESP32-S2 series of products, including ESP32-S2 SoCs, ESP32-S2 modules and ESP32-S2 development boards. Document Updates Please always refer to the latest version on https://www.espressif.com/en/support/download/documents.

  • Page 3: Table Of Contents

    3.10.1 Q: The current ripple is not large, but the TX performance of RF is rather poor. 3.10.2 Q: The power ripple is small, but RF TX performance is poor. 3.10.3 Q: When ESP32-S2 sends data packages, the power value is much higher or lower than the target power value, and the EVM is relatively poor.
  • Page 4 ESP32-S2 RF Matching Schematic ESP32-S2 PCB Layout ESP32-S2 Module Antenna Position on Base Board Keepout Zone for ESP32-S2 Module’s Antenna on the Base Board ESP32-S2 Power Traces in a Four-layer PCB Design ESP32-S2 Crystal Oscillator Layout ESP32-S2 RF Layout in a Four-layer PCB Design...

  • Page 5: Overview

    MCU. ESP32-S2 includes a Wi-Fi subsystem that integrates a Wi-Fi MAC, Wi-Fi radio and baseband, RF switch, RF balun, power amplifier, low noise amplifier (LNA), etc. The chip is fully compliant with the IEEE 802.11b/g/n protocol and offers a complete Wi-Fi solution.

  • Page 6: Schematic Checklist

    ESP32-S2’s integrated circuitry requires only 20 resistors, capacitors and inductors, one crystal and one SPI flash memory chip. ESP32-S2 integrates a Wi-Fi MAC, Wi-Fi radio and baseband, RF switch, RF balun, power amplifier, low noise amplifier (LNA), and advanced calibration circuitries.

  • Page 7: Power Supply

    PCB board. 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 3.6 V.

  • Page 8: Analog Power Supply

    Figure 3: ESP32­S2 Analog Power Supply Pins Notice: • The recommended voltage of the power supply for ESP32-S2 is 3.3 V, and its recommended output current is 500 mA or more. • It is suggested that users add an ESD protection diode at the power entrance.

  • Page 9: Power-On Sequence And System Reset

    Notice: To ensure the power supply to the ESP32-S2 chip during power-up, it is advised to add an RC delay circuit at the CHIP_PU pin. The recommended setting for the RC delay circuit is usually R = 10 kΩ and C = 1 µF. However, specific parameters should be adjusted based on the power-up timing of the power supply and the power-up and reset sequence timing of the chip.

  • Page 10: Crystal Oscillator

    PSRAM-3V3 Figure 4: ESP32­S2 Flash and SRAM 2.4 Crystal Oscillator There are two clock sources for the ESP32-S2, that is, an external crystal oscillator clock source and an RTC clock source. 2.4.1 External Clock Source (compulsory) Currently, the ESP32-S2 firmware only supports 40 MHz crystal oscillator. The specific capacitive values of C1 and C4 depend on further testing of, and adjustment to, the overall performance of the whole circuit.

  • Page 11: Rtc (Optional)

    10nF 40MHz(±10ppm) Figure 6: Schematic for ESP32­S2’s Crystal Oscillator 2.4.2 RTC (optional) ESP32-S2 supports an external 32.768 kHz crystal or an external signal (e.g., an oscillator) to act as the RTC sleep clock. GPIO10 Figure shows the schematic for the external 32.768 kHz crystal.
  • Page 12 VDD33 2.0nH 2.5 RF The impedance matching point for the RF pin (pin2) of ESP32-S2 is (34+j5) Ω. A π-type matching network is 0.1uF 10uF essential for antenna matching in the circuit design. CLC structure is recommended for the matching network.

  • Page 13: Uart

    To solve this issue, add an external pull-up resistor. 2.7 USB The ESP32-S2 has a full-speed USB OTG peripheral with integrated transceivers and is compliant with the USB 1.1 specification. GPIO19 and GPIO20 can be used as D- and D + of USB respectively. It is recommended to reserve series resistor and capacitor to the ground on each line, and place them close to the chip side.

  • Page 14: Pcb Layout Design

    3. PCB Layout Design 3. PCB Layout Design This chapter introduces the key points of designing ESP32-S2 PCB layout with the example of ESP32-S2 mod- ule. 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.

  • Page 15: Positioning An Esp32-S2 Module On A Base Board

    Figure 11: ESP32­S2 Module Antenna Position on Base Board Note: As is shown in Figure 11, the recommended position of ESP32-S2 module on the base board should be: • Position 3, 4: Highly recommended; • Position 1, 2, 5: Not recommended.

  • Page 16: Power Supply

    • As shown in Figure 13, an ESD protection diode is placed close to the power port (marked in red circle). A 10 µF capacitor is required before the power trace connects the ESP32-S2 chip, to be used in conjunction with a 0.1 µF capacitor.

  • Page 17: Crystal Oscillator

    • As the crystal oscillator is a sensitive component, do not place any magnetic components nearby that may cause interference, for example large inductance component, and ensure that there is a clean large-area ground plane around the crystal oscillator. Espressif Systems ESP32-S2 Hardware Design Guidelines V1.1 Submit Documentation Feedback...
  • Page 18 It is good practice to add ground vias around the UART signal line. • When doing 50 Ω single-ended impedance control for the RF trace, please refer to the PCB stack-up design shown in Figure 16. Espressif Systems ESP32-S2 Hardware Design Guidelines V1.1 Submit Documentation Feedback...

  • Page 19: Flash And Psram

    Place the reserved serial resistor on the SPI communication line close to the chip side. Route the SPI traces on the inner layer (e.g., the third layer) whenever possible. Add ground vias around the clock and data traces of SPI separately. The layout of the flash and PSRAM on ESP32-S2 is shown in Figure 17. Espressif Systems ESP32-S2 Hardware Design Guidelines V1.1...

  • Page 20: Uart

    Note to surround the USB traces with ground copper. 3.9 Touch Sensor ESP32-S2 offers up to 14 capacitive IOs that detect changes in capacitance on touch sensors due to finger contact or proximity. The chip’s internal capacitance detection circuit features low noise and high sensitivity. It allows users to use touch pads with smaller area to implement the touch detection function.
  • Page 21 • The trace width (W) can not be larger than 0.18 mm (7 mil). • The alignment angle (R) should not be less than 90°. • The trace-to-ground gap (S) should be in the range of 0.5 mm to 1 mm. Espressif Systems ESP32-S2 Hardware Design Guidelines V1.1 Submit Documentation Feedback...
  • Page 22 • The traces should be isolated well and routed away from that of the antenna. Figure 20: Sensor Track Routing Requirements In addition, ESP32-S2 touch sensor adopts a waterproof design and features proximity sensor function. Figure shows an example layout of a waterproof and proximity sensing design.

  • Page 23: Typical Layout Problems And Solutions

    Solution: Add a 10 µF filter capacitor to the branch of the power trace (the branch powering the ESP32-S2 analog power pin). The 10 µF capacitor should be as close to the analog power pin as possible for small and stable current ripples.

  • Page 24: Q: When Esp32-S2 Sends Data Packages, The Power Value Is Much Higher Or Lower Than The Target Power Value, And The Evm Is Relatively Poor

    Solution: Keep the antenna away from crystal oscillators. Do not route high-frequency signal traces close to the RF trace. Please see Section for details. Espressif Systems ESP32-S2 Hardware Design Guidelines V1.1 Submit Documentation Feedback...

  • Page 25: Hardware Development

    • The serial tool cannot be used for both the log-print and flash-download tools simultaneously. 4.2 ESP32­S2 Development Boards For a list of the latest designs of ESP32-S2 boards please check Development Boards section of Espressif web- site.

  • Page 26: Revision History

    Revision History Revision History Date Version Release notes 2020-11-18 V1.1 Updated the capacitance of RC circuit to 1 µF in 2.2.1. 2020-05-07 V1.0 First release. Espressif Systems ESP32-S2 Hardware Design Guidelines V1.1 Submit Documentation Feedback...

Table of Contents