Great little convertor smaller then the size of my pinky finger nail. The output voltage is very stable. I use it on a battery powered ESP8266 to feed the 3.3v input directly. Because I am using the Wemos D1 mini I cut the track to the UART to reduce power consumption, see image. In deep sleep mode my configuration takes about 500uA, or 0.5mA The ESP should use about 17uA, so the rest is used by the convertor. Before this I used a 5v convertor to feed the USB input. That used 1500uA (3x more). 4 stars because I had hoped for a better power efficiency of the convertor. But for now it's fine.
Great little convertor smaller then the size of my pinky finger nail. The output voltage is very stable. I use it on a battery powered ESP8266 to feed the 3.3v input directly. Because I am using the Wemos D1 mini I cut the track to the UART to reduce power consumption, see image. In deep sleep mode my configuration takes about 500uA, or 0.5mA The ESP should use about 17uA, so the rest is used by the convertor. Before this I used a 5v convertor to feed the USB input. That used 1500uA (3x more). 4 stars because I had hoped for a better power efficiency of the convertor. But for now it's fine.