Smart Meter Service Disconnect Switches From Fairchild Semiconductor

The best solutions integrate service disconnect switches with accurate input filter timing, XOR input protection, the maximum output pulse-width to protect the relay, and the configurability of either following the input or to always provide a pre-defined maximum pulse width.

To enable these functionalities, Fairchild Semiconductor has developed the FAN3240 & FAN3241 smart dual-coil relay drivers. The family provides strong DC output currents to safely open and close a relay contactor and has a wide operating voltage range to use with relays of several voltage rating. The devices also integrate a linear regulator from a single unregulated bias supply that allows for both non-isolated and isolated designs.

Key Features:

•8 V to 60 V operating range for use with 12 V, 24 V or 48 V relays
•Strong DC current to break through welded contacts without using external switches
•Accurate input filter time (factory adjustable) and XOR input protection
•Accurate maximum output pulse width (factory adjustable)
•Output can follow input width or give maximum limit (mode factory adjustable)
•Internal thermal shutdown protection
•Single bias voltage design for the chip allows isolated and non-isolated designs
•Inputs compatible with 3.3 V or 5 V square-wave logic signals
•Enable pin for operational flexibility



The FAN324x family of smart dual-coil relay drivers with integrated switches and wafer-level adjust capability for timing customization, is available in an 8-lead SOIC package and is part of Fairchild’s continuing efforts to create innovative power management solutions for smart meters and renewable energy.

Packaging and Pricing Information (in US 1,000 quantity pieces)

Samples available upon request - Delivery 8-12 weeks ARO.

Available in an 8-lead SOIC package, the FAN324x is priced at $0.85.