Espressif Systems ESP32-S3 - USB; SDIO; Touch Sensor

Chapter 4. PCB Layout Design
Fig. 14: ESP32-S3 UART Layout
The UART layout should meet the following guidelines:
• The series resistor on the U0TXD trace needs to be placed close to the chip side and away from the crystal.
• The U0TXD and U0RXD traces on the top layer should be as short as possible.
• The UART trace should be surrounded by ground copper and ground vias stitching.
4.8 USB
The USB layout should meet the following guidelines:
• Place the RC circuit on the USB traces close to the chip side.
• Use di󰝗erential pairs and route them in parallel at equal lengths.
• Make sure there is a complete reference ground plane and surround the USB traces with ground copper.
4.9 SDIO
The SDIO layout should follow the guidelines below:
• Since SDIO traces have a high speed, it is necessary to control the parasitic capacitance.
• The trace length for SDIO_CMD and SDIO_DATA0 ~ SDIO_DATA3 should be 3 mil longer or shorter than
the trace length for SDIO_CLK. If necessary, use serpentine routing.
• It is better to surround the SDIO_CLK trace with ground copper. The path from SDIO GPIOs to the master
SDIO interface should be as short as possible and no more than 2500 mil or even 2000 mil.
• Do not place SDIO traces across planes.
4.10 Touch Sensor
ESP32-S3 o󰝗ers up to 14 capacitive IOs that detect changes in capacitance on touch sensors due to 󰝘nger contact or
proximity. The chip’s internal capacitance detection circuit features low noise and high sensitivity. It allows to use
touch pads with smaller area to implement the touch detection function. You can also use the touch panel array to
detect a larger area or more test points.
Figure ESP32-S3 Typical Touch Sensor Application depicts a typical touch sensor application.
To prevent capacitive coupling and other electrical interference to the sensitivity of the touch sensor system, the
following factors should be taken into account.
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