We are using the LM5066I configured with a dv/dt startup as per datasheet/application note.
The datasheet itself does not specify a minimum slew rate and in fact states that the smaller the better. I have also had a searched online but did not find anything against small slew rate.
We are currently using 0.09V/ms giving us a startup time in the range of 580ms. (VinMax = 53V, Coutmax 2000uF). This appears to work correctly and we are getting the expected slew rate & startup time.
The confusion comes from the "LM5066I Design Tool- Rev. C" excel sheet which helps design this circuit. This document DOES implement a minimum slew rate of 0.12V/ms.
The worksheet sheet used for calculation implements the limit in the following cells with hardcoded values: (Note, this is in a locked, hidden sheet titled dv_dt_recommendations)
| Upper bound Slew Rate (4ms start-up) (V/ms) | 12 |
| Min Slew Rate (400 ms start - up) (V/ms) | 0.12 |
Question 1: Is the minimum slew rate implemented in the excel workbook an arbitrary low value to allow this workbook to work correctly or is their an underlying IC limitation?
Question 2: The document refers to a 400ms startup, but the datasheet does not mention a maximum startup time, is their an IC limitation?
Regards,
Alexis
