JAJSH18A March 2019 – September 2019 TPS7A78
The device requires a surge resistor or resistors in series with the AC+ and or AC– pins, depending configuration; see the Full-Bridge (FB) and Half-Bridge (HB) Configurations section for details. The purpose of the surge resistor is to limit the hot-plug AC current into the AC+ and AC– pins when the AC supply voltage is applied. Equation 10 calculates the value of the minimum surge resistor RS (MIN) required for the application.
If the solution requires the use of a transient voltage surge suppressor (TVS) or a metal-oxide varistor (MOV), then use the maximum clamping voltage of the TVS or MOV instead of the peak VAC voltage in Equation 10. After calculating RS(MIN), select the next-higher standard resistor value.