Hi,
We can find the soft start time setting with Rss resister on datasheet P.8. If my customer set the different resister which is not in the list, what is soft start time? Please let us know the formula with soft start time and resisters.
Thanks and best regards,
M.HATTORI.
Hattori-san,
The TPS543B20 uses 10 discrete soft-start times that are selectable with the resistance on the SS pin. Upon startup, the TPS543B20 will apply a current source at the SS pin, read the voltage, and then internally select the soft-start time. If the customer is using a different resistor than those specified in table 1, I cannot guarantee the SS time selection as the device will interpret the voltage as a discrete selection.
For example, if the customer uses say a 10 kohm resistor on the soft-start pin, the device will read the voltage and decipher the soft-start time as either 1ms or 2ms based on its internal logic. This has not been fully characterized, which is why the table indicates that E48 resistors with 1% tolerance are recommended as these are the values we validate/test for this part.
Can the customer use one of the resistances in the table above?
Regards,
Alec Biesterfeld
