Datasheet FL7921R (ON Semiconductor) - 5

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FL7921R PIN DEFINITIONS
(continued)
Pin # Name Description
12 RT Adjustable over−temperature protection. A constant current is flowed out of the RT pin. When the RT pin voltage is lower than 0.8 V (typical), the controller stops all PFC and PWM switching operation and enters auto recovery protection mode. 13 VIN Line−voltage detection for brown−in / out protections. This pin can receive the AC input voltage level through a voltage divider. The voltage level of the VIN pin is not only used to control RANGE pin’s status; (ZCD) can also perform brown−in / out protection for AC input voltage UVP. 14 ZCD Zero−current detection for the PFC stage. This pin is connected to an auxiliary winding coupled to PFC inductor winding to detect the ZCD voltage signal once the PFC inductor current discharges to zero. When the ZCD voltage signal is detected, the controller starts a new PFC switching cycle. When the ZCD pin voltage is pulled to under 0.2 V (typical), it disables the PFC stage and the controller stops PFC switching. This can be achieved with an external circuit if disabling the PFC stage is desired. 15 NC No connection 16 HV High−voltage startup. HV pin is connected to the AC line voltage through a resistor 100 kW (typical) for providing a high charging current to VDD capacitor.
ABSOLUTE MAXIMUM RATINGS Symbol Parameter Min Max Unit
VDD DC Supply Voltage − 25 V VHV HV Pin Voltage − 500 V VH OPFC, OPWM Pin Voltage −0.3 25.0 V VL Others (INV, COMP, CSPFC, DET, FB, CSPWM, RT) −0.3 7.0 V VZCD Input Voltage to ZCD Pin −0.3 12.0 V PD Power Dissipation − 800 mW qJA Thermal Resistance (Junction−to−Air) − 104 C/W qJC Thermal Resistance (Junction−to−Case) − 41 C/W TJ Operating Junction Temperature −40 +150 C TSTG Storage Temperature Range −55 +150 C TL Lead Temperature (Soldering, 10 Seconds) − +260 C ESD Human Body Model, JESD22−A114 (All Pins Except HV Pin) (Note 3) − 5 kV Charged Device Model, JESD22−C101 (All Pins Except HV Pin) (Note 3) − 2 Stresses exceeding those listed in the Maximum Ratings table may damage the device. If any of these limits are exceeded, device functionality should not be assumed, damage may occur and reliability may be affected. 1. Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. 2. All voltage values, except differential voltages, are given with respect to the GND pin. 3. All pins including HV pin: CDM = 0.5 kV, HBM = 1 kV.
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