CAP400DGCAPZero-4 Zero Loss Automatic X-Capacitor Rapid Discharge IC Product Highlights • Blocks current through X capacitor discharge resistors when AC R1 voltage is connected • Automatical y discharges X capacitors through discharge resistors D1 when AC is disconnected • Meets IEC 60335 X capacitor discharge to below 34 V in less than 1 MOV second AC X Capacitor and Other EMI Filter • Supports X capacitor values up to 6 mF Components • Simplifies EMI filter design – larger X capacitor al ows smal er inductive components D2 • Meets safety standards for use before or after system input fuse CAP400DG • >4 mm creepage on package and Printed Circuit Board (PCB) R2 • Self supplied – no external bias required PI-7507b-102425 • High common mode surge immunity – no external ground connection • High differential surge withstand – 900 V internal MOSFETs Figure 1. Typical Application. • EN/IEC 62368-1 (NEMKO), UL 62368-1 (UL), and GB 4943.1 (CQC) certification Component TableEcoSmart– Energy EfficientTotal Series • <0.75 mW consumption at 230 VAC for any capacitor value Product2BVTotalResistance1DSSX Capacitance(R1 + R2)Applications • Al AC-DC converters with X capacitors between 100 nF and 6 mF • Appliances requiring ErP Lot 6 compliance CAP400DG 900 V 100 nF to 6 mF 50 kW Minimum 100 kW Maximum • Adapters requiring ultra low no-load consumption • Al converters requiring very low standby power Table 1. Component Table. Notes: Description 1. Nominal Values. 2. Package: D: SO-8. When AC voltage is applied, the CAP400DG IC blocks current flow through the X capacitor safety discharge resistors, reducing the power loss to less than 0.75 mW at 230 VAC. When AC voltage is discon- nected, the CAP400DG IC automatical y discharges the X capacitors by connecting the series discharge resistors. This operation allows flexibility in the choice of the X capacitor to optimize differential mode EMI filtering and reduce inductor cost. Designing with CAP400DG IC is simply a matter of selecting the appropriate external resistor values to meet the necessary X-capacitor discharge time. Figure 2. SO-8 D Package. www.power.com June 2026 This Product is Covered by Patents and/or Pending Patent Applications.