ZHCSHJ8C December 2017 – November 2019 TVS0500
If the TVS0500 is in place to protect the device, during a surge event the voltage will rise to the breakdown of the diode at 7.9 V, and then the TVS0500 will turn on, shunting the surge current to ground. With the low dynamic resistance of the TVS0500, large amounts of surge current will have minimal impact on the clamping voltage. The dynamic resistance of the TVS0500 is around 30 mΩ, which means 30 A of surge current will cause a voltage raise of 30 A × 30 mΩ = 0.9 V. Because the device turns on at 7.9 V, this means the LDO input will be exposed to a maximum of 7.9 V + 0.9 V = 8.8 V during surge pulses, well within the absolute maximum input voltage. This ensures robust protection of your circuit.
The small size of the device also improves fault protection by lowering the effect of fault current coupling onto neighboring traces. The small form factor of the TVS0500 allows the device to be placed extremely close to the input connector, lowering the length of the path fault current will take through the system compared to larger protection solutions.
Finally, the low leakage of the TVS0500 will have low input power losses. At 5 V, the device will see typical 70 pA leakage for a constant power dissipation of less than 1 nW, a negligible quantity that will not effect overall efficiency metrics or add heating concerns.