Hi,
Our customer is considering to remove the components for transient protection indicated by (note 1) to reduce system cost around eFuse.
The load is wireless module not for inductance load such as motors.
Are there any concern to remove the components ?
Thank you and best regards,
Michiaki
Hi Michiaki,
A TVS at the input and Schottky at the output are required to clamp Positive voltages at input and negative voltages at the output during transients respectively.
The Spikes are generated due to parasitics on the input and output path as shown below.
In case customer tests thoroughly all transient conditions (like short circuit at output) and see that the voltages at input and output are within the limits as per the device datasheet then they are good to go without TVS and Schottky.
Hi Michiaki,
Yes, your understanding is correct.
As efuse does circuit breaking operation for continuous over-currents or short circuit conditions, a TVS and Schottky is required for protecting the device from Transient over voltages.
In some cases, the TVS can be avoided for eFuse. For example, if you are operating a 20V eFuse but your operating voltage is only 5V, the transient voltage spikes can be less than 20V. in this case the device is still safe without a TVS.
On the other hand, PTC is just a resistor which increases its resistance when the dissipation in it increases. As it does not do fast turn Off operation, transient over voltages are not expected.
Below is a comparison table between eFuse and PTC for your reference.
