I have a APM 2.5.2 (From 3DRobotics) with a burned out TPS79133DBVR 3.3v regulator.
But I live in Brazil and I could not find this component here, to buy from the USA it would be too expensive (almost US$ 100 with shipment and taxes......)
But searching for orher 3.3 100mA with a 5-Pin SOT23 (DBV) Package I could find the TPS76933.
Is that regulator a good substitute for the TPS79133?
Open farnell.com and search for LDO, then select 3.3V and all fields from 100 to 250mA + the SOT-23/5 case field.
You'll see a lot of compattible LDOs. Then check those with pin1 = IN, pin2 = GND, pin3=EN, pin 4 = bypass capacitor, pin5=OUT. That's it.
That is how I found the TPS76933!!
The only problem I see with TPS79133 is that EN is low level signal, in opposite to most other LDOs which have EN=high. You need to check the PCB layout for to see whether the EN is tied to VCC or to GND, then to choose the appropriate LDO.
The TPS76933 is EN=Low
The main difference is that it does not have the BP and have a simpler inner schematics - but at least I could find it to buy around here.