BP35C5 - Wi-SUN FAN Sub-GHz Transceiver Module | ROHM

Smart Electricity Metering

The BP35C5 fits smart electricity meter deployments because Wi-SUN FAN was designed specifically for utility field area networks, and the module carries Wi-SUN Alliance certification (WSA0218) plus FCC certification for the 902-928 MHz North American ISM band. Its -105 dBm receiver sensitivity and 13.8 dBm output power deliver the link budget required for multi-hop mesh topologies where meters relay traffic for neighbors. The integrated 32-bit MCU runs the full Wi-SUN FAN stack, exposing a simple UART command interface so the meter's main MCU does not need protocol firmware or extra flash. The 2.6 V to 3.6 V supply range accommodates typical meter power architectures. Designers should budget for an external 902-928 MHz antenna and verify the module's NRND status against the meter program's production lifetime before committing.

Street Lighting Control Networks

Street lighting controllers benefit from the BP35C5's Wi-SUN FAN mesh networking, which self-heals as luminaires are added or removed and supports frequency-hopping resilience across the 902-928 MHz band. The module's -105 dBm sensitivity enables long hop distances between pole-mounted nodes, reducing gateway density in wide-area deployments. Because the mesh protocol runs on the module's integrated 32-bit MCU and is accessed via UART and GPIO, lighting-controller firmware stays simple; the ROHM application manual shows GPIOA0/SDA (pin 18) providing LED network-status indication useful during field commissioning. The 2.6-3.6 V supply integrates easily with the aux power present in luminaire drivers. Note the module is antenna-less by design, so a pole-appropriate 902-928 MHz antenna and FCC-conforming installation are required.

Smart City Infrastructure

Smart city nodes - environmental sensors, parking sensors, and public-safety endpoints - use the BP35C5 to join Wi-SUN FAN mesh networks that scale across a metropolitan area. Wi-SUN is an international standard optimized for smart communities, and the BP35C5's certification (WSA0218, FCC) shortens end-product regulatory work substantially compared with a discrete radio design. The 300 kbps maximum data rate is sufficient for telemetry and control traffic typical of city infrastructure, while the mesh topology provides redundant paths through other city nodes. UART and GPIO host interfaces allow integration with virtually any host controller. Because the module is NRND, smart-city program managers should confirm supply lifetime or design in ROHM's current Wi-SUN module generation for new deployments.

Gas and Water Meter AMI

Advanced metering infrastructure (AMI) for gas and water uses battery-assisted endpoints, making the BP35C5's integration attractive: the module runs the Wi-SUN FAN stack internally, so the meter's low-power host MCU spends minimal energy managing the network. The 2.6 V to 3.6 V input range matches a single lithium primary cell with a regulator, and UART wake/command traffic keeps host complexity low. The 902-928 MHz Sub-GHz band offers better propagation and penetration than 2.4 GHz for pit and basement installations, and -105 dBm sensitivity preserves mesh connectivity in challenging metal-rich environments. Verify local regulatory acceptance of the 902-928 MHz band plan, and plan for the external antenna and FCC installation conditions in the enclosure design.

Industrial Telemetry and Monitoring

Industrial telemetry endpoints - tank levels, pump status, and environmental monitoring across plant grounds - can leverage the BP35C5 to form Wi-SUN FAN meshes where running cable is uneconomical. The module's UART interface allows an existing PLC-adjacent controller to send and receive telemetry frames with simple AT-style commands, while GPIO handles status and flow control. Its 13.8 dBm output and -105 dBm sensitivity give roughly 119 dB of raw link budget, supporting long hops between buildings or across a facility, with mesh routing adding redundancy around obstructions. The -55C to +155C rated temperature range (per distributor specification data) covers harsh outdoor enclosures. Note that NRND status makes this module best suited to evaluation and legacy service rather than new industrial designs.

Wireless Sensor Network Gateways

Wi-SUN border routers and gateways can use the BP35C5 as the Sub-GHz radio front end, bridging the mesh network to backhaul Ethernet or cellular. Because the module is Wi-SUN FAN and FCC certified, gateway makers avoid designing and certifying a discrete 902-928 MHz radio. The UART host interface forwards mesh traffic to the gateway processor, and the 300 kbps air rate is adequate for aggregating metering and sensor traffic from hundreds of nodes. The GPIOA0/SDA status output (per the ROHM application manual) can drive a network-activity LED for field diagnostics. Gateways are long-lifecycle infrastructure products, so the module's NRND status is a serious consideration - verify last-time-buy planning with ROHM before design-in.