SLUSD37E October 2017 – November 2019 UCC28056
Switching edge spikes imposed on the signal feeding this pin may cause the internal ESD structures to conduct, causing a voltage offset to appear on the capacitive divider feeding this pin. To limit this risk, place the voltage divider close to the ZCD/CS pin and far from the region of fast changing magnetic field. See the shaded area show in Figure 37. Maintain a small number of nets between the resistors and capacitors in the divider to limit capacitive pickup within the divider chain. Maintain the loop identified in Figure 36 small and contain the minimum area to limit magnetic pickup. Run the connections between the current sense resistor and UCC28056 directly to the terminals of resistor and not be shared with power circuit traces.
When laying out the PCB start with the ZCD/CS pin divider placement and routing to ensure that the needs of this pin come first.