The SPBTLE-1S from STMicroelectronics has the entire Bluetooth Low Energy stack and protocols embedded right into the module. Based on the BlueNRG-1 SoC, this Bluetooth RF module can be powered directly with a pair of AAA batteries or any power source from 1.7 to 3.6 V.
The SPBTLE-1S is a BLE application processor module with embedded ceramic antenna that is compliant with Bluetooth specifications v4.2. Originally designed around the ST BlueNRG-1 SoC, the module features a Cortex-M0 core that can execute both the Bluetooth protocols and the user’s application. It also enables applications to adhere to the tight advisable peak current requirements imposed with the use of standard coin cell batteries. Most interesting, however, is the fact that the active mode supply current is a minor 1.9 mA and the sleep mode is 0.9 uA!