BK3231 Bluetooth HID SoC  Datasheet 

Technical Description 
The brief circuit description is listed as below: 
1) U1 acts as a 2.4GHz IC (BK3231). 
2) X1 acts as a Crystal for U1. 
Antenna Type: Internal antenna 
Antenna Gain: 0dBi 
Nominal rated field strength: 85.2 dBμV/m at 3m 
Maximum allowed field strength of production tolerance: +/- 3dB

General Description 
The BK3231 chip is a highly integrated single-chip Bluetooth3.0HID device. It integrates the high-performance transceiver, rich features baseband processor, and Bluetooth HID profile. The FLASH program memory makes it suitable for customized application, and it is also possible for other Bluetooth aplication such as SPP controller. 
Features 
Operation voltage from 2.0V to 3.6 V  Bluetooth 3.0compliant -86dBm sensitivity for 1 Mbps mode and 2 dBm transmit power HID v1.0, and other light profile by request 16 MHz crystal reference clock 56-pin QFN 7mmx7mm package for keyboard I2C, SPI and UART interface 10-bit Battery monitor ADC Three timers with PWM mode