Brian Dorey has previously torn down several Amazon Echo devices including the 3rd gen Dot, 3rd gen Dot with Clock, the Flex, and the Echo Input. This teardown looks the new Echo Dot 4th generation model which is a smart speaker with the Amazon Alexa service.
The top of the smart speaker has four buttons, four microphones and an LED ring. The + and – buttons control the volume; the circle button activates Alexa and the circle with a line through it enables or disables the microphones.
This new version of the Echo Dot uses different processor to the previous Echo Dot models. A MediaTek 2GHz dual-core ARM CPU with Amazon AZ1 Neural Edge processor, part number MT8512BAAV and a SK Hynix LPDDR4 SDRAM 4G-Bit RAM IC (H9HCNNN4GUML) which are located under a metal shield.
Below the CPU and Ram is a MediaTek Wi-Fi / Bluetooth Controller, part number MT7653BSN which has outputs to two PCB antennas, one on each side of the board.
On the switch board:
On the reverse of the circuit board are four microphones and a TLV320ADC5140 Texas Instruments Quad-channel 768-kHz Burr-Brown™ audio analogue to digital converter. There are several other smaller ICs on the board, but we could not find any information on what they are.
The Echo dot uses the four microphones to locate the direction the voice is coming from and filter out background noise.
See the video below and more on the blog post here.