Engineered to replace discrete relay circuitry, the CPC2501M from Littelfuse is the first application-specific integrated circuit (ASIC) in the Littelfuse portfolio for this function. It integrates self-protection, fault timing, and solid-state switching into a single compact 6×6 mm QFN package—simplifying video doorbell integration while enhancing reliability and safety.
“The CPC2501M chime bypass relay enables video doorbell manufacturers to make their product work with existing house installations,” said Hugo Guzman, Product Marketing Manager, Integrated Circuits Division, Littelfuse. “End users can replace the doorbell button with a new video doorbell unit using the existing door chime box—no need for specialised installation or added circuitry.”
Key benefits:
- Integrated self-actuating logiceliminates the need for external microcontrollers or software control
- Built-in fault protection timer (~17 seconds) automatically resets during prolonged button presses or chime failure
- High-performance switchingwith 60 VP bidirectional voltage and 1.84 ARMS continuous load current
- Peak current capability of 5 Afor handling start-up and surge conditions
- Thermally optimised 6×6 mm QFN-16 packageconserves PCB space for compact module designs
- Installablebehind standard 8–24 VAC doorbell transformers
As video doorbell adoption grows, so does the challenge of powering these devices using legacy home wiring and mechanical chimes. The CPC2501M addresses this challenge by creating a power bypass path when the chime is inactive and instantly turning off that path during doorbell operation—ensuring continuous power to the camera unit and full chime functionality without complex retrofitting.
While optimised for door chime bypass in video doorbell systems, the CPC2501M is also well suited for:
- Building automation controls
- IoT devices with voltage-controlled actuation
- Security systems requiring compact, solid-state switching
- General-purpose voltage-controlled relay designs
By integrating multiple protection and logic functions, the CPC2501M simplifies design and installation while improving durability and performance in consumer and industrial environments.
