X-CAP Bleeder

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Product Description

HF81 is an innovative two-terminal IC that automatically discharges an X capacitor while eliminating power losses and allowing power supplies to comply with safety standards. The HF81 acts as a smart high-voltage switch when placed in series with discharge resistors (alternatively bleed resistors). In the presence of an AC voltage, the HF81 blocks current flow in the safety discharge resistors to reduce the power loss in these components to zero at 230 VAC. When disconnected from the AC voltage, the HF81 automatically and safely discharges the X capacitor by closing the circuit through the bleed resistors and directing the energy away from the exposed AC plug. Table 1: Component Selection Table PN X Capacitance Total Series Resistance Power Saving(1) HF81 =500nF 1.5MO 750nF 1MO 66mW 1? 780kO 86mW 1.5? 480kO 142mW 2? 360kO 191mW 2.5? 300kO 230mW 3.5? 200kO 347mW 5? 150kO 464mW

Product Features

  • Disconnect series discharge resistors from L-N when AC voltage is applied
  • Connect series discharge resistors with L-N to discharge the X capacitor when AC voltage is unplugged
  • Supplied by AC voltage directly and doesn? need external bias
  • Meets safety standards for use before or after input fuse
  • No external ground pin leads to high common mode surge immunity
  • 1000V internal JFET inside leads to high differential surge immunity
  • >4mm creepage on package and PCB


  • Power Range DefinedNo
  • GradeCatalog
  • Vbr (V)1000
  • Isupply (µA)15
  • Isc (mA)1.7