I know I’m not supposed to have favorites, but what the Ambiq engineers have been able to accomplish is quite extraordinary. They have been able to achieve power levels that are below the competition, with performance that’s more than adequate. See the Garmin Forerunner 940 Smartwatch as an example (including my Tear Down report of said watch).

Ambiq just announced the next generation of its SoC CPU family, named Apollo4. The parts are built on TSMC’s 22-nm ULL process. The secret sauce comes in the form of the company’s Subthreshold Power Optimized Technology (SPOT) platform, which allows optimization of the MCU’s active and sleep mode power states. In fact, the active mode is specified at 3 μA/MHz. That’s about half the spec of Ambiq’s previous generation.

The Apollo4 can serve either as an applications processor or as a coprocessor for things like smartwatches, fitness bands, animal trackers, far-field voice remotes, predictive health and maintenance devices, smart security devices, and smart home devices. The power levels are suited for applications that require a coin cell lasting for years, in some cases. This is significant for places where changing a battery can be difficult.

The Apollo4 is designed around an Arm Cortex M4 processor core with floating-point unit. The maximum clock frequency is 192 MHz. A second core, an M0, handles some of the housekeeping functions. The SoC can also contain a Bluetooth Low Energy (BLE) 5 radio (in the Apollo4 Blue version) that includes direction-finding Angle of Arrival (AOA) and Angle of Departure (AOD) for always-on applications. Always-on voice processing is handled through the proprietary audio interfaces and low-power analog microphone.

The Apollo 4 family is sampling now. Package options include a 146-pin BGA and a 121-lead WLCSP. A full SDK with reference code is also available.