Connected devices fail in production for reasons a dev-board prototype never reveals: an enclosure that detunes the antenna, a battery that drains in weeks instead of years, or a production line with no way to load unique device credentials. Planning these early saves board re-spins and tooling changes.
1. Module or chip-down?
| Factor | Pre-certified module | Chip-down design |
|---|---|---|
| Engineering effort | Lower | Higher (RF layout, matching, testing) |
| Radio certification | Often simplified by the module’s modular approval | Full intentional-radiator testing |
| Unit cost | Higher | Lower at high volume |
| Board size | Larger | Smaller |
| Best for | Low-to-medium volume, faster launch | High volume, tight size or cost targets |
2. Antenna and enclosure are one design
- Keep metal, batteries and ground planes away from the antenna keep-out area
- Test RF performance in the real enclosure material — some plastics, coatings and fillers affect it
- For metal enclosures, plan an external antenna or an RF window early
- Seal design (gaskets, ultrasonic welding) must not interfere with antenna placement
3. Power budget
Measure real current profiles (sleep, wake, transmit) on the production design, not datasheet values. Reporting interval, network join behaviour and retries usually dominate battery life. Choose the battery chemistry with the operating temperature range in mind.
4. Design for production test and provisioning
- Test points or a test connector for programming and functional test
- A defined production test: power-up, sensors, radio link, current consumption
- A provisioning step that writes unique IDs, keys or certificates — with secure handling of credentials
- Labels and QR codes that match the provisioned identity
- Firmware version control and a way to update devices in the field
See the PCB assembly files checklist for what the assembler needs.
5. Build stages for IoT products
The EVT / DVT / PVT stages apply fully. For IoT, add field trials during EVT/DVT — real networks and real installation environments reveal coverage and power issues that lab tests miss.
6. Plan certification from the start
Radio products need market-specific approvals. Choosing modules, antennas and enclosure materials affects how much testing is required. Read our certification overview for connected devices, and see IoT hardware for how we support connected products from prototype to production.