The FAN41501 is a digital controller for periodic functional testing of key Ground Fault Circuit Interrupters (GFCI) components. In combination with an existing ON Semiconductor GFI controller, it periodically tests for the functional operation of the GFCI controller, solenoid, sense transformer, SCR, and other discrete components without disrupting power to the load or compromising normal GFCI protection functionality. If the FAN41501 detects a faulty GFCI component, it generates an End-of-Life (EOL) fault signal that can be used to deny power and/or automatically reset after the denial of power.When the AC power is first applied, an internal timer starts a test cycle at one second. After this initial test cycle, the internal timer starts a test cycle every 90 minutes. During a test cycle, the FAN41501 simulates a ground fault and monitors the key GFCI components. If the FAN41501 detects a component fault, it verifies the fault several times to prevent a false EOL signal. At no time during a test cycle is the normal GFCI protection disabled or compromised.The FAN41501 includes a 5 V shunt regulator, one-second timer, 90-minute timer, digital control logic, detection comparators, and an EOL driver output.The FAN41501, together with a GFCI controller such as FAN4149, provides a complete UL943 GFCI function with automatic monitoring capability, low system power, and a minimum number of external components.The 6-pin, SuperSOT™ package enables a low-cost, compact design and layout.