While optional, external circuit components can be used to extend the robustness of the RES80A-Q1 and further protect sensitive downstream circuitry.

• To provide additional margin against high-edge-rate transient events, such as in applications requiring extremely high ESD ratings, consider implementating a high-voltage bypass capacitor or capacitor string at the device input. This parallel path acts to shunt the high-frequency signal and bypass the RES80A-Q1, dissipating the surge energy outside the device, without impacting the dc and low-frequency precision of the device. Refer to Layout Examples for implementation.
  • Verify that creepage and clearance requirements are respected, and be aware that additional input capacitance can extend system step-response settling times.
  • Testing of an input protection network consisting of a ferrite bead and three 2000V, X7R bypass capacitors in series has been shown to extend ESD pass levels to more than ±12kV; refer to the RES60A-Q1 Extended Reliability Testing application note.
  • In some systems upstream capacitances such as Class-X or Class-Y capacitors, or even the stacked cells of a battery pack, fill this role and inherently provide some degree of additional protection. Select and validate the protective scheme according to the application requirements.
• During HIPOT testing and at peak input voltages, the RES80A-Q1 continues to act as a resistive divider while the high-voltage stress is applied, so the voltage at the MID pin rises accordingly. Verify that all downstream circuitry at and after MID is properly clamped with protective diodes (such as Schottky diodes) or is rated to withstand the associated voltage rise.
  • A TVS diode, such as TSD05C, between the MID and LVIN pins provides additional clamping protection against fast transients for downstream low-voltage circuitry, if necessary. Refer to the System-Level ESD Protection Guide and ESD Protection Layout Guide application notes for additional information.
• A deliberate filtering or compensation capacitor C_FILTER in parallel with R_LV permits gain-shaping at high frequency according to circuit or application needs, and helps to protect downstream circuitry from fast transients. While use of a large C_FILTER value causes high-frequency noise to be strongly attenuated, if C_FILTER is excessively large the step response of the device is slowed.
  • Parasitic board capacitances also add with C_FILTER, possibly resulting in a larger effective C_LV than intended. Therefore, choose a value of C_FILTER based on the application requirements, and use the final printed circuit board implementation to verify the device performance meets design goals.