Espressif ESP8266 WiFi-serial interface : weekend die-shot

Since August of 2014 internet is literally blown by WiFi-serial modules on new ESP8266 chip which are currently being sold for less than 4$ . Chinese company Espressif managed to cram entire WiFi, TCP/IP and HTTP stack into on-chip memory, without external DRAM. Analog front-end requires minimal external components, all filters are internal. All this allowed them to offer extremely aggressive price. Chip has marking ESP8089, which is their more advanced 40nm product. Apparently, they only differ in bonding and ROM content.Die size 2050x2169 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.Chinese engineers did an outstanding job here on finally making WiFi IoT devices cost effective. Let's hope Espressif will eventually open more internal chip information for amateurs and end users.