March 2026 – Silicon Labs Streamlines Wireless PIR Design
Silicon Labs has announced the BG24-PIR, a dedicated system-on-chip (SoC) designed specifically for wireless PIR motion sensors. The device integrates an analog front-end for pyroelectric sensors, a low-power ARM Cortex-M33 processor, and a multi-protocol radio (Bluetooth, Zigbee, Thread, Matter) in a single package.
Key Features
Integrated Analog Front-End
- Dual-channel programmable gain amplifier (20-80 dB gain range)
- 16-bit sigma-delta ADC with 1 µV resolution
- Programmable high-pass and low-pass filters
- Integrated voltage reference and bias generation for PIR elements
- Automatic offset cancellation
Ultra-Low Power Consumption
- Sensor monitoring mode: 2.5 µA (AFE + wake-on motion logic)
- MCU sleep: 1.2 µA with RAM retention
- Radio receive: 4.5 mA
- Radio transmit (0 dBm): 5.2 mA
- Supply voltage: 1.8V to 3.8V (direct battery connection)
On-Chip Motion Detection
The BG24-PIR includes hardware accelerators for motion detection:
- Programmable threshold detection with hysteresis
- Direction detection for dual-element sensors
- Pattern matching for pet/human discrimination
- Automatic hold time and block time generation
Wireless Connectivity
- Bluetooth 5.4 with direction finding
- Zigbee PRO and Thread
- Matter-ready
- Proprietary 2.4 GHz modes
- Integrated PA with up to +8 dBm output
Benefits for Designers
- Reduced component count: Replaces separate AFE, MCU, and radio
- Smaller PCB: 5mm × 5mm QFN package
- Faster time-to-market: Pre-certified radio and reference designs
- Lower power: Optimized for PIR applications
- Flexible protocols: Same hardware supports multiple ecosystems
Reference Designs
Silicon Labs is offering two reference designs:
Coin-Cell Battery Design
- CR2032 battery
- 10-year battery life (10 events/day)
- 25mm × 25mm PCB
- Panasonic EKMB PIR element
Energy Harvesting Design
- Solar or thermoelectric harvester
- Supercapacitor storage
- Maintenance-free operation
- Excelitas PYD 2597 PIR element
Software and Tools
- Simplicity Studio: Development environment with PIR examples
- Mobile App: iOS/Android app for configuration and testing
- ML Toolkit: Tools for training custom motion classification models
- Cloud Integration: Ready-to-use code for AWS IoT, Google Cloud, and Azure
Pricing and Availability
The BG24-PIR is available now for sampling, with volume production scheduled for Q3 2026. Pricing starts at $1.89 in 10,000-unit quantities. Evaluation boards are available for $79.
Industry Impact
“This is the first SoC designed from the ground up for PIR sensing,” said a Silicon Labs product manager. “By integrating the analog front-end, we’ve eliminated the need for external op-amps and comparators, reducing BOM cost and power consumption. We expect this to accelerate the adoption of wireless PIR sensors across all markets.”