The PCB of the IOT and wearable devices need to achieve ultra-low power consumption, stable wireless communication, and tolerance to complex environments under extreme spatial constraints. Through material innovation (flexible/nano coating), process upgrades (HDI/LDS), and system level optimization, they can meet users' rigid requirements for portability, long battery life, and seamless connectivity.
The core principles are as follows:
IoT devices and wearable devices (such as smartwatches, health monitoring bracelets, sensor nodes, etc.) need to achieve a balance between miniaturization, low power consumption, wireless communication, and adaptability to complex environments. The following are the areas that we focus on during the production and assembly process:
O Use flexible circuit boards (FPC) or rigid flex boards to meet bending requirements (such as smart watch strap bending radius ≤ 3mm).
Ultra thin substrate (thickness ≤ 0.4mm), paired with HDI (high-density interconnect) process, through-hole diameter ≤ 0.1mm, line width/spacing ≤ 50 μ m.
Use 01005 packaged components (0.4mm × 0.2mm) or wafer level packaging (WLCSP) to achieve an integration density of>500 pins/cm ².
Antenna integration: Directly engrave antennas (such as Bluetooth/Wi Fi
2.4GHz frequency band) on PCBs through LDS (Laser Direct Molding) technology.
Adopting dynamic voltage regulation (DVFS) and deep sleep mode, with static current ≤ 1 μ A (such as button battery devices with standby time>1 year).
O Use ultra-low power MCU (such as Nordic nRF series) and energy harvesting module (solar/kinetic energy conversion efficiency>15%).
The charging management circuit supports wireless charging (Qi standard), and the coil is integrated into the inner layer of the PCB with a thickness of ≤ 0.2mm.
The lithium battery protection circuit needs to pass UL 2054 certification, with an overcharge/overdischarge protection response time of less than 10ms.
O Antenna impedance matching (50 Ω± 5%), using π - type matching network or T-type topology to reduce return loss (S11 ＜ -10dB).
The RF wiring adopts a coplanar waveguide (CPW) structure to avoid crossing the segmented reference layer and ensure signal integrity.
Install conductive foam or nanocrystalline magnetic shielding sheets in sensitive areas and pass FCC Part 15B and CE RED radiation tests.
The clock signal line uses serpentine wiring or ground wire wrapping to suppress harmonic interference.
Spray nano hydrophobic coating (contact angle>150 °) to achieve IP67/IP68 protection level (such as swimming wristbands).
The connector adopts waterproof rubber plug or laser welding sealing, and has been tested for 1000 hours at 85 ℃/85% humidity.
The FPC board has passed 100000 bending tests (radius 2mm, angle 180 °), and the copper foil elongation rate is greater than 15%.
The components are fixed using Underfill or UV curable adhesive, with a drop resistance height of ≥ 1.5m (MIL-STD-810G).
SMT surface mount accuracy ± 25 μ m (requires 3D SPI detection) to prevent virtual soldering of micro solder joints.
Use selective welding technology to avoid overheating and deformation in flexible areas (temperature control ± 3 ℃).
Wireless performance testing: Verify OTA (over the air transmission) efficiency>40% in a microwave anechoic chamber.
Power consumption test: Simulate real scenarios (such as heart rate monitoring+Bluetooth transmission), with a total power consumption of ≤ 10mW.
The wireless communication module needs to pass FCC/CE/RoHS certification and support multiple frequency bands (such as LoRa 868MHz/915MHz).
Biosensors (such as blood oxygen monitoring) must comply with ISO 13485 or FDA 21 CFR Part 820 (medical grade wearable devices).
Integrate hardware encryption chips (such as ATECC608A) that support AES-256/SHA-256 algorithms to prevent data tampering.
