In general, the TPS23521 is designed to have robust operation from a non-ideal –48 V bus with various transients such as the lightning surge. The IC is powered through RVCC making it more immune to supply drop outs and high voltage spikes. Regardless, TI recommends following several key precautions:

• Always test the solution with the various transients that can be encountered in the systems. This especially applies to transients that were not tested with TI’s EVM.
• If large input ripple is expected during start-up, increase the ratio of C_{SS, VEE} to C_SS to reduce input current ripple at start-up.
• Operating from large input inductance (>40 µH) can cause instability to the current limit loop or oscillations during start-up. Add a capacitor from Gate to VEE to help stabilize the current limit loop. Add an input snubber if oscillations are observed at start-up.