David,
Hopefully, the following answers to your questions will help you decide on whether the ADP5050 meets your design needs.
1. I need to use the 200 mA LDO as 5.4V input and 5V output (and 150mA) is it possible? how much voltage drop in that case?
It is possible to drive a 5V output @ 150mA from the LDO in this device when supplied by 5.4V at the input. Care should be taken to not exceed the 5.5V input range of the LDO. The dropout voltage in this condition will be approximately 120mV.
2. What kind of current limit associated with ADP5050 LDO? fold-back? constant current? latch? auto recovery?
The LDO current limit provides a constant current output. The output voltage will recover when the fault condition is removed. The current limit protection is intended to protect the device against accidental overload conditions.
3. Accept the Overvoltage Latch-Off Mode is there another buck output over voltage protection? what about the LDO over voltage protection? is it associated with the Overvoltage Latch-Off Mode mechanism?
There are no other overvoltage protections on the outputs other than the selectable overvoltage latch-off mode for the buck converters. The LDO does not include overvoltage protection on its output.
4. Does one output over current protection effect the other outputs somehow?
The overcurrent protection for each output is independent of the other outputs. The four buck converters have the option of latching-off in a short circuit condition and each channel can be re-enabled by writing to the appropriate register bit in the LCH_STATUS register. The LDO output should recover after the fault condition is removed unless the device shutdown due to an overtemperature condition.
Thank you,
Travis B