Description
The NCS37012 is a fully UL943 compliant signal processor for GFCI applications with self test. The device integrates a flexible power supply (including both shunt and LDO regulators), differential fault, and grounded-neutral detection circuits. Proprietary impedance measurement and signal processing techniques are used to minimize the number of external components and improve performance. The device also includes a specialized DSP controller that offers best in class immunity to nuisance loads without the need for external analog filters. Self test is monitored every 17 minutes through an external current path and internally generated grounded neutral fault.

FEATUREs
• 6.0 V − 12 V Operation (120 − 480 V AC mains with the appropriate series impedance)
• −40 to 85°C
• Very Low Power Consumption: <15 mW @ 5 V
• 16 Pin QFN Package or 20 Pin TSSOP Package
• Single Current Transformer (CT) Detection of both Differential and Grounded−Neutral Faults
• Full Self Test and Trip Indicator Monitoring
• Self Syncing Internal Oscillator Adjusts to AC Mains Frequency to Guarantee Full Resolution on 50 and 60 Hz Distribution Systems
• Optimized Solenoid Deployment (coil is not energized near the AC mains zero crossings)
• Randomized Testing Sequence to Minimize Noise and Potential Interactions on the AC Mains
• >5 mA SCR Driver for use with High Igt SCR’s for Improved Noise Immunity
• Superior Immunity to Nuisance Loads/Noise (up to 10 A) without Loss of Detection Capability or CT Saturation
• These Devices are Pb−Free, Halogen Free/BFR Free and are RoHS Compliant

Typical Applications
• Load Panel GFCI Breakers
• GFCI Receptacles
• In−line GFCI Circuits (power cords)