Espressif ESP8266 WiFi-serial interface

Espressif ESP8266 WiFi-serial interface : weekend die-shot blog posting shows what is inside ESP8266 WiFi IoT chip. Die size 2050×2169 µm, half of which is occupied by transceiver and PA, 25% – on-chip memory (rough size estimations are ~300KiB), and the rest is Xtensa LX106 CPU core and other digital logic. Chip has marking ESP8089, which is their more advanced 40nm product. Apparently, they only differ in bonding and ROM content.