Wireless MCU Design Guide: BLE 5.0 and Sub-1GHz
Wireless design requires attention to RF, power, and regulatory requirements. This guide covers best practices for Hangshun Wireless MCUs.
Protocol Selection
BLE 5.0: 2.4GHz frequency; Smartphone connectivity; 2Mbps high-speed mode; Coded PHY for long range; Best for: Consumer devices, phone accessories.
Sub-1GHz: 433/868/915MHz options; Long range (1-5km); Better penetration; Lower interference; Best for: Industrial sensors, smart metering.
Decision Matrix: Need smartphone connection �?BLE; Maximum range required �?Sub-1GHz; High data rate �?BLE; Long battery life, low data �?Sub-1GHz.
Antenna Design
antenna Types: PCB antenna: Compact, lowest cost; Chip antenna: Small, moderate performance; External antenna: Best performance, larger size.
PCB Antenna Guidelines: Follow reference design exactly; Keep ground clearance as specified; No copper in keep-out area; Test with network analyzer.
Matching Network: PI network for tuning; Match to 50Ω; Consider bandwidth requirements; Production tolerance considerations.
Power Optimization
BLE Power Saving: Use long connection intervals (up to 4s); Enable slave latency; Optimize TX power for range needs; Deep sleep between transmissions.
Sub-1GHz Power: Lower duty cycle for battery life; Use LoRa for very low power; Optimize data payload size; Implement listen-before-transmit.
Battery Life Calculation: Calculate average current; Determine duty cycle; Size battery for target lifetime; Consider self-discharge.
PCB Layout for RF
Critical Guidelines: Keep RF traces short and straight; 50Ω controlled impedance for RF lines; Adequate ground vias around RF section; No digital traces under RF section.
Component Placement: Antenna at board edge; Crystal close to MCU; Decoupling capacitors near power pins; Separate ground for RF and digital.
Certification Requirements
BLE Certification: Bluetooth SIG qualification; FCC/CE/IC radio certification; Test reports required; QDID for listing.
Sub-1GHz Certification: FCC Part 15 (USA); ETSI EN 300 220 (Europe); ARIB (Japan); SRRC (China).
Pre-Certified Modules: Simplify end product certification; Faster time to market; Limited modification allowed; Module integration guide available.
Development and Testing
Development Tools: Protocol analyzers for debugging; Power profilers for optimization; Range testing tools; Certification test modes.
Testing Checklist: RF performance (TX power, sensitivity); Power consumption (active, sleep); Protocol compliance; Range in target environment.
Troubleshooting
common RF Issues: Poor range �?Check antenna matching, ground; High current �?Verify sleep modes, clock gating; Connection drops �?Check interference, range; Certification failures �?Review layout, filtering.
💡 FAE Insights
📋 Customer Cases
IoT Sensor Company
Industrial IoT
Challenge
Customer experienced poor range and high battery consumption in their first wireless sensor design
Solution
FAE identified antenna matching issues and recommended PCB layout changes. Optimized connection intervals and sleep modes.
Customer Feedback
"Range improved from 50m to 200m after fixing antenna matching. Battery life extended from 6 months to 3 years with power optimization."
Frequently Asked Questions
1. Should I choose BLE 5.0 or Sub-1GHz for my application?
Selection criteria: BLE 5.0 - Smartphone connectivity; 2Mbps data rate; Interoperability; Best for consumer devices. Sub-1GHz - 2-5x longer range; Better penetration; Lower interference; Best for industrial sensors. Comparison: Range (urban): BLE 30-50m, Sub-1G 100-500m; Data rate: BLE 2Mbps, Sub-1G 50-500kbps; Power: Similar with proper duty cycling.
2. What is the range of Hangshun wireless MCUs?
Range depends on protocol and environment: BLE 5.0 - 1Mbps: 30-50m indoor, 100-150m outdoor; Coded PHY: 100-200m indoor, 300-500m outdoor. Sub-1GHz - 433MHz: 500m-1km urban, 2-5km rural; 868/915MHz: 300-800m urban, 1-3km rural. Factors: Frequency, TX power, sensitivity, antenna, obstacles.
3. How do I optimize power for battery-operated wireless devices?
Power optimization strategies: Duty cycling - Minimize active time; Sleep >99% of time. Connection intervals - Longer intervals = lower power; BLE: 7.5ms to 4s. TX power - Use minimum for required range; -20dBm to +8dBm adjustable. Data aggregation - Collect before transmission; Burst vs frequent small packets. Sleep modes - Deep sleep with RAM retention: <1μA. Example: Sensor reading every minute with BLE: ~6μA average; CR2032 battery: 4+ years.
4. What security features do Hangshun wireless MCUs provide?
Security features: Hardware encryption - AES-128/256 accelerator; 10-100x faster than software. Secure boot - Verify firmware signature; Prevent unauthorized code execution. Key storage - Secure key storage; Hardware-protected slots. BLE security - Pairing: Just Works, Passkey, OOB; Encryption: AES-128-CCM; Privacy: Resolvable addresses. Implementation: Enable secure boot; Use authenticated pairing; Encrypt sensitive data; Regular security updates.
5. What certification is required for wireless products?
Certification requirements: BLE - Bluetooth SIG qualification; FCC/CE/IC radio certification. Sub-1GHz - FCC Part 15 (USA); ETSI EN 300 220 (Europe); ARIB (Japan); SRRC (China). Process: Pre-testing at certified lab; Documentation preparation; Regulatory submission; ID labeling. Pre-certified modules: Simplify certification; Faster time to market; Limited modifications allowed.