For IoT edge-node devices or “connected” health and wellness applications, designers must consider at least the following parameters when comparing system power consumption levels between Bluetooth low energy radio SoCs:
- Power Conversion: Most Bluetooth low energy radio SoCs operate at wide input voltage levels to satisfy the needs of different batteries. However, the battery voltage is most often different from the operating voltage of the Bluetooth low energy RF path as well as the operating voltage of on-chip Flash, processing cores, and memory. Hence, effective on-chip power conversion becomes important to get to the lowest possible power consumption.
- Duty-cycling: Receiving (Rx) and Transmitting (Tx) currents are obviously important for the power budget; however, the paradox of most Bluetooth low energy applications is that most of the time they aren’t actually doing anything. Sampling, transmission and reception of data typically happens at very low data rates, which is why the sleep current of the device often becomes the dominant factor in the application’s overall power budget.
In response to the rapidly evolving needs of IoT and “connected” health and wellness applications, ON Semiconductor has the RSL10, a multi-protocol Bluetooth®5 certified radio SoC, offering the industry’s lowest power.
For RSL10, its defining “ultra-low-power” characteristic begins in applications that are typically battery powered (e.g., devices using 1.5 V AAA batteries, 3 V 2032 coin cells, 1.25 V 10A ZnAir batteries), and where the data throughput during normal operation is relatively low.
The Bluetooth low energy RF path of RSL10 operates “natively” at 1.1 V but, to ensure that battery voltages ranging from 1.1 V up to 3.6 V can be accommodated, RSL10 facilitates effective, on-chip DC/DC conversion as well as regulation to feed other parts of the system with appropriate voltages.
For instance, if the RSL10 is powered by a 3 V 2032 coin cell (which would be the case in many medical or remote sensing IoT applications), the following Sleep Mode currents can be achieved:
- 25 nA with wake-up from external pin.
- 40 nA with wake-up from external pin or internal timer.
- 100 nA with wake-up from external pin or internal timer and 8 kB RAM retention.
Most alternative Bluetooth low energy radio SoCs require two to three times the amount of current to maintain similar modes.
Additionally, RSL10 draws 3.4 mA in Rx Mode and 4.6mA in Tx Mode – in both cases these numbers are achievable using the 2 Mbps data rate established by the new Bluetooth 5 standard.
So how do these numbers apply in a real world scenario where an application developer needs to calculate battery life time based on knowledge about the duty cycling of the application?
Consider the example shown in the figure below, where a remote sensing application is in its active Bluetooth low energy transmit duty cycle once every 2 seconds of its operating life. The remaining time the application is in Sleep Mode (wake-up from external pin) or not transmitting or receiving data.
Bluetooth Low Energy Technology Duty Cycle Power Considerations
For a complete advertising event with a 24-byte payload (Transmit power 0dBm), RSL10 will consume approximately 700 uA for a duration of 7 ms. Using this information, it is easy to relate the Bluetooth low energy power consumption to the battery capacity.
Features:RSL10 SoC and SiP:
- Industry's lowest power consumption in Deep Sleep Mode (62.5 nW) and Rx in Receive Mode (7 mW)
- Industry's best EEMBC® ULPMark™ scores (1090 ULPMark CP @ 3 V; 1260 @ 2.1 V)
- Rx Sensitivity: 94 dBM
- Transmitting Power: -17 to +6 dBM
- Supports Bluetooth Low Energy and 2.4 GHz proprietary/custom protocols
- Supports Firmware Over The Air (FOTA)
- Built-in power management
- Advanced dual-core architecture
- 1 to 3.3 Voltage Supply Range
- 384 kB Flash, 76 kB Program Memory, 88 kB Data Memory
- IP protection feature to secure flash contents
- Configurable analog and digital sensor interfaces (GPIOs, LSADs, I2C, SPI, PCM)
- IoT Edge-Node Applications
- Bluetooth Low Energy Technology
- FCC (U.S.)*
- CE (Europe)*
- IC (Canada)*
- KCC (Korea)*
- MIC (Japan)*
RSL10 Software Development Kit (SDK)
- Includes Bluetooth protocol stacks, sample code, libraries, documentation
- Arm Cortex-M3 processor development (GNU toolchain)
- Eclipse with C Development Toolkit (CDT)
- CMSIS packages
RSL10-002GEVB - Radio SoC evaluation board:
The RSL10 development board is used to easily develop Bluetooth® low energy technology-enabled applications based on the industry’s lowest power radio System-on-Chip (SoC).
- Compliance with the Arduino form factor
- Support for PMOD (e.g., J4 is a standard connector)
- On-board J-Link feature for simple debugging
- Alternate on-board SWJ-DP (serial-wire and/or JTAG) for ARM® Cortex® -M3 processor debugging
- Access to all RSL10 peripherals via standard 0.1" headers
- On-board 4-bit level translator to translate the LPDSP32 debug interface at a low voltage to a 3.3 V JTAG debugger
- Antenna matching and filtering network
- Integrated PCB antenna
RSL10-COIN-GEVB - Ultra-low power temperature sensor beacon:
RSL10-COIN-GEVB is a coin cell operated ultra-low power Bluetooth beacon. The board incorporates a temperature sensor, NCT375, and RSL10, the beacon follows Eddystone, an open beacon format from Google. A web URL and ambient temperature data embedded in the advertising packet can be read using Beacon Scanner or other freely available beacon scanning apps from the Android and iOS app stores.
RSL10-SIP-001GEVB - RSL10 SIP Development Board:
With an Arduino-compliant form factor and on-board J-Link adaptor, the RSl10 SIP development board is used to effortlessly develop Bluetooth® low energy applications based on the RSL10 System-in-Package (SiP).
Features and Applications:
- Integrated antenna (included as part of the RSL10 SIP)
- Onboard 4-bit level translator to translate the LPDSP32 debug interface at low voltage to a 3.3 V JTAG debugger
- Access to all RSL10 SIP peripherals via standard 0.1″headers
- Alternate on-board SWJ−DP (serial-wire and/or JTAG) interface for Arm® Cortex®−M3 processor debugging
- On-board J-link adaptor provides a SWJ−DP (serial-wire and/or JTAG) interface that enables you to debug the board using a USB connection to the PC
- Compliance with the Arduino form factor
RSL10 SoC IC - Available at RS