Capacitor Discharge IC 8-Pin SOIC

When AC voltage is applied, CAPZero blocks current flow in the X capacitor safety discharge resistors, reducing the power loss to less than 5 mW, or essentially zero1 at 230 VAC. When AC voltage is disconnected, CAPZero automatically discharges the X capacitor by connecting the series discharge resistors. This operation allows total flexibility in the choice of the X capacitor to optimize differential mode EMI filtering and reduce inductor costs, with no change in power consumption. Designing with CAPZero is simply a matter of selecting the appropriate CAPZero device and external resistor values for the X capacitor value being used. This design choice will provide a worst case RC time constant, when the AC supply is disconnected, of less than 1 second as required by international safety standards. The simplicity and ruggedness of the two terminal CAPZero IC makes it an ideal choice in systems designed to meet EuP Lot 6 requirements. The CAPZero family has two voltage grades: 825 V and 1000 V. The voltage rating required depends on surge requirement and circuit configuration of the application.

• Maximum X Capacitance : 1 µF
• Total Series Resistance2 (R1 + R2) : 780 k?
• Blocks current through X capacitor discharge resistors when AC voltage is connected
• Automatically discharges X capacitors through discharge resistors when AC is disconnected
• Simplifies EMI filter design – larger X capacitor allows smaller inductive components with no change in consumption
• Only two terminals – meets safety standards for use before or after system input fuse
• >4 mm creepage on package and PCB
• Self supplied – no external bias required
• High common mode surge immunity – no external ground connection
• High differential surge withstand – 1000 V internal MOSFETs