We are using the LM2937-3.3 linear LDO voltage regulator to get 3.3V from 5V.
Output current is 50mA maximum.
LM2937-3.3 DATASHEET:
**broken link removed**
The previous engineer has placed a series Schottky diode (D12) following the LM2937 (i.e, the Schottky is immediately upstream of the output cap as in following diagram)
…..the load has been represented as a resistor, but actually it’s a MC13211 RF Transceiver which has a 2V to 3.4V operating voltage with on-chip voltage regulators….(3.6V max recommended input voltage as per page 46 of the datasheet)
I think previous engineer wants to obtain 3v from that regulator, and don't have available a 3V regulator. Or, maybe it wants to prevent reverse spikes from load. I don't see any other reason, it's not necessary.