This blog was updated on 11/19/15 by Svein Vetti to include information about the Sub-1 GHz solution in this family.
The new SimpleLink™ CC26xx/CC13xx ultra-low power platform for Bluetooth® low energy, 6LoWPAN, ZigBee®, Sub-1 GHz and ZigBee RF4CE™ is built and designed with low power in mind. In the following, we have looked at all aspects important to making sure the energy footprint of our solution is as small as possible enabling longer battery lifetimes, smaller batteries or even energy harvesting for battery-less applications.
Contrary to popular belief, that radio transceiver itself is not always the main contributor to the overall power consumption of a wireless microcontroller (MCU). As various technologies progress, there is more and more need for computing power even at relatively small sensors and the wireless protocol stacks come with more overhead as the standards evolve.
In the SimpleLink CC26xx/CC13xx family, there are two very energy efficient MCUs available for the application.
The ARM Cortex-M3 is the main system CPU inside the CC26xx/CC13xx device. One way of measuring the performance of MCUs is by using benchmark tools. One of the more popular benchmarks is CoreMark from the Embedded Microprocessor Benchmark Consortium (EEMBC). CoreMark is a simple, yet sophisticated, benchmark that is designed to test the efficiency of a processor core used in embedded devices. It is not system dependent, therefore it functions the same regardless of the platform (e.g big/little endian, high-end or low-end processors etc.). This benchmark also demonstrates the energy efficiency of the MCU core.
Table 1: Various CoreMark scores for the CC26xx/CC13xx, measured on 7ID @ 3.0V and 48MHz
The scores in Table 1 allow for very low average power consumption during active use. Running the ARM Cortex-M3 at maximum speed (48MHz) the CPU operation consumes less than 3 mA and outperforms any wireless MCU running at less efficient cores or at lower CPU clocks. The CC26xx Coremark power efficiency (CoreMark / mA) is the best compared to any competitor with a comparable MCU, making it the most energy efficient microcontroller available today.
The unique ultra-low power sensor controller is a 16-bit CPU coupled with peripherals like analog to digital converter (ADC), analog comparators, SPI/I2C and capacitive touch. It is designed to run autonomously when the rest of the system is in standby. The Sensor Controller allows interface with external analog or digital sensors in a very low power manner.
Figure 1: The ultra-low power sensor controller engine can run autonomously while the rest of the system is in standby
Waking up the entire system to perform minor tasks is very often not energy-efficient as it introduces a lot of overhead. In many use cases there are tasks that need to run at certain intervals that are at a higher duty-cycle than the actual RF or main activity.
One example could be a heart-rate monitor that needs to run the ADC 10 times per second to capture the heart rate accurately. Waking the entire system up to perform a wireless transmission 10 times per second will in this case be very energy inefficient. With the SimpleLink ultra-low power platform, one can let the Sensor Controller perform all the ADC measurements and wake up the ARM Cortex-M3 every 10th ADC sample for optional further processing and group RF transmission of this data.
Figure 2: The sensor controller can significantly reduce average power consumption
In this example the sensor controller can do 10 ADC reads per second at less than 3 uA average consumption. Performing the same task using the ARM Cortex-M3 will require 10x the power consumption.
Table 2: Energy efficiency of the sensor controller while running at the main clock.
The sensor controller can run directly off a pre-scaled 24 MHz clock, making it capable of collecting data and performing simple processing of the data.
Sleep and shutdown
How average current affects battery lifetime
Table 3: Average scores for the CC26xx/CC1310 measured on CC2650-7ID @ 3.0V
All of what has been discussed comes into play when looking at the power profile of a wireless event. Figure 4 shows a connection event for Bluetooth low energy with wake-up, pre-processing of the software stack, radio events (both receive and transmit) and a post-processing / going back to sleep period.
Figure 4: Power profile of a Bluetooth low energy connection event
Further details on how to calculate average currents and battery-lifetime for a Bluetooth low energy application can be found in 
For additional information about Sub-1 GHz in the Internet of Things read this new white paper: Diversifying the IoT with Sub-1 GHz technology
To get started developing with this SimpleLink ultra-low power platform, order one of our new LaunchPad™ development kits
- CC2650 LaunchPad kit for Bluetooth low energy, ZigBee and 6LoWPAn
 Marketing Malarkey and Some Truths About Ultra-Low Power Design, Jack Ganssle 2014
 EEMBC ULPBench