The ESP32-PICO-D4 is a System-in-Package (SiP) that is based on ESP32, supporting both Wi-Fi and Bluetooth connectivity, yet avoiding bulky quad-flat no-leads (QFN) packages. The module’s dimensions are only 7.0 × 7.0 × 0.94 mm, which means that it requires minimal PCB area, while integrating a 4 MB SPI flash, a crystal oscillator and most of the decoupling caps. This “makes life a lot easier and reduces via and component count”, as IoTbits acknowledges.
With its small size, robust performance and low-energy consumption, ESP32-PICO-D4 is an ideal solution for wearable electronics and other space-constrained applications.
ESP32-PICO-D4 SiP specifications:
On a different note, the ESP32-S0WD chip is also a member of the ESP32 family, which has been designed to achieve the best power and RF performance, with robustness, versatility, and reliability in a wide variety of applications. The distinctness of ESP32-S0WD is based on the fact that it features a single core, while maintaining the combination of Wi-Fi and Bluetooth connectivity.