The TEA1708 is an automatic discharge IC for X capacitors with a low power consumption (typically 1 mW at 230 V (AC).
A 500 V clamping circuit is integrated, protecting the IC during mains surges. In a typical application with only two 200 kΩ resistors, the maximum differential mode mains surge voltage allowed exceeds 6 kV. A metal oxide varistor is not required to protect the IC.
The X capacitor discharge current is internally limited to 2.3 mA. The discharge delay timer is set externally using a low voltage capacitor.
The very low power consumption in combination with a large discharge current enables the use of a large value X capacitor to reduce EMI while retaining the low standby power.