onsemi NCS37021 Self-Test GFCI
onsemi NCS37021 Self-Test Ground Fault Circuit Interrupter (GFCI) is a UL943-compliant signal processor for GFCI applications with self-test capabilities. The device integrates a flexible power supply (including a 12V shunt, two 3.3V internal series regulators, and a 1.8V internal regulator), differential fault, and grounded-neutral detection circuits. The self-test of the onsemi NCS37021 is monitored at startup and then every minute.
Features
- Meets UL943 self-test GFCI requirements
- 4.0V to 12V operation (120VAC to 480VAC mains with the appropriate series impedance)
- Wide -40°C to +95°C operating temperature range
- Low quiescent current
- Optimized solenoid deployment (coil is not energized near the AC mains zero crossings)
- Power supply monitor that verifies full diode bridge operation
- Tiered GF trip times that increase immunity to noise
- Under-voltage detection allows for increased operation at lower AC input voltages
- Intelligent sensing differentiating ground fault versus ground neutral fault (prevent nuisance tripping)
- 16-pin QFN package
- Lead-free
Applications
- GFCI receptacles
- Load panel GFCI breakers
- In-line GFCI circuits (power cords)
Simplified Block Diagram
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