Espressif provides the SMD module-ESP-WROOM-02 that integrates ESP8266EX. The module has been adjusted to get the best RF performance. We recommend using ESP- WROOM-02 for tests or for further development.

The module size is 18 mm (±0.2 mm) x 20 mm (±0.2 mm) x 3 mm (±0.15 mm). The type of flash used on this module is an SPI flash with a package size of SOP 8-150 mil. The gain of the on-board PCB antenna is 2 dBi.

• ESP-WROOM-02 is a low-power 32-bit MCU Wi-Fi module, based on the ESP8266 chip. TCP/IP network stacks, 10-bit ADC, and HSPI/UART/PWM/I2C/I2S interfaces are all embedded in this module.
• ESP-WROOM-S2 uses a 2 MB SPI flash connected to HSPI, working as the SDIO/SPI slave with the SPI speed of up to 8 Mbps.
• ESP8266 Module can be easily integrated into space-limited devices, due to its small size of only 18mm x 20mm (ESP-WROOM-02) / 16 mm x 23 mm (ESP-WROOM-S2).
• Reliable and most certificate:
  • Wi-Fi Alliance, SRRC, FCC, CE, TELEC, IC & KCC Certified
  • RoHS, Halogen Free, REACH & CFSI Compliant
  • HTOL, ESD-HM, MSL, μHAST, HTSL
  • Output Power: +22dBm peak power in FCC certification
• ESP8266 Module can operate in low-power connectivity mode; for instance, if it operates in DTIM10, it only consumes 1.2mW while maintaining a Wi-Fi connection. The module also integrates an SPI flash of 16 Mbits used for storing user programs, data and firmware.
• Module is directly supplied from Espressif, sufficient stock and constant price.

1. Datasheet - ACM ESP8266 WROOM-02 WIFI MODULE