Compact Wearable IoT Device

A compact, battery-powered wearable device featuring Wi-Fi and Bluetooth connectivity for portable applications.

Design Overview

System Architecture

Power Topology: Single-cell Li-ion battery (3.7V nominal, 300-500mAh) connected to BQ25120A PMIC, stepping down to a clean 3.3V main rail via integrated low-quiescent buck converter, supplying MCU, wireless subsystems, and sensors.

Module List

Design Schemes

Dual-Core Wireless SoC with Advanced PMIC ★

Utilizes a dual-core application and wireless SoC paired with a low-quiescent PMIC and custom ceramic antenna for compact skin-contact wearability.

Trade-offs: Optimizes PCB footprint and skin-temperature dissipation better than discrete multi-chip solutions, while maintaining high Wi-Fi/BLE performance.

Single-Chip RISC-V IoT Architecture

Employs an all-in-one RISC-V SoC with integrated Wi-Fi 6, BLE, and 802.154 for ultra-compact, cost-optimized wearable production.

Trade-offs: Lower BOM cost and reduced PCB complexity, but relies on a single processing core for both application and wireless duties.

Key IC selection

dual-core application processor and wireless companion

• Need: Provide dual-core processing for real-time BLE stack execution, application logic, and low-power Wi-Fi 6 interfacing within a constrained wearable power envelope.
• Class: Dual-core ARM Cortex-M33 SoC with companion Wi-Fi 6 companion IC
• Shortlist: Nordic nRF5340 + nRF7002, Realtek RTL8730EH, Espressif ESP32-H2 + ESP32-C6 (multi-chip approach)
• Pick: Select based on Bluetooth LE multiprotocol maturity, ultra-low sleep current consumption, combined solution footprint, and unified software ecosystem support.

battery charger and power management IC

• Need: Provide safe linear charging for a small Li-ion cell while generating highly efficient low-Iq step-down and LDO rails for the MCU and sensors.
• Class: Linear Li-ion battery charger with integrated nano-power buck converter and LDOs
• Shortlist: Texas Instruments BQ25120A, Analog Devices LTC4124, Maxim Integrated MAX77650
• Pick: Choose based on quiescent current in ship mode, programmable output voltage steps, integrated protection features, and ultra-small WQFN package size.

dual-band antenna matching and radiation

• Need: Radiate and receive 2.4GHz (BLE/Wi-Fi) and 5GHz (Wi-Fi 6) RF energy efficiently while minimizing detuning effects caused by proximity to human tissue.
• Class: SMD ceramic chip antenna with discrete Pi-matching network
• Shortlist: PulseLarsen W3027 / similar dual-band ceramic chip, Taoglas FXP830 flexible PCB antenna, Yageo / TDK multilayer ceramic chip antennas
• Pick: Select based on clearance requirements, omnidirectional gain profile, small footprint, and empirical VNA tuning performance on the final wearable mechanical enclosure.

Risk register

Key Components

5/6 modules matched to real parts. See the BOM tab for the full component table.

Texas Instruments BQ25120A (BQ25120)

The candidate BQ25120 matches the primary MPN BQ25120A (base part number match with acceptable ordering suffix differenc

Texas Instruments BQ27421-G1A (BQ27421)

The candidate matches the primary MPN BQ27421 and belongs to the correct component class (Integrated Circuits) from Texa

Nordic Semiconductor nRF5340 + nRF7002 (nRF7002-EB)

Candidate 2 is an evaluation board (nRF7002-EB) from Nordic Semiconductor corresponding to the primary MPN nRF7002.

Custom Ceramic Chip Antenna with Pi-matching (2400AT43A5600E)

Web recommendation: 2400AT43A5600E (not in ES)

Build Summary

• Difficulty: Advanced
• Estimated time: 6-8 hours
• Tools required: Anti-static tweezers, Component storage trays, Solder paste stencil, Squeegee, Type 4 SAC305 Solder Paste, Precision vacuum pen

See the Build tab for the full step-by-step assembly guide.

Generated by YuanQi AI Design System · Query: Hardware design project based on the uploaded circuit schematic/image.