HT7333 is a low power low drop out (LDO) linear regulator and you may consider using it in many energy-constrained projects. However, there is no in-depth performance chart shown in the datasheet, so I decided to perform a simple test to investigate the drop-out voltage in different loads. Mainly under 50ma, 100ma, 200ma and 300 ma.
I soldered a 0.75mm2 wire to the leg directly to reduce the heat lost in the wire (compared to Dupont) as well as added two 10uF capacitors to the input and output of HT7333 to comply with the datasheet.
***I am using a low-end virtual load and power supply, the readings are not very accurate. I tried a few trials and the result varies quite a bit.
Under 50ma load, HT7333 proform the best. The output voltage starts to drop at around 3.5v input and the drop out voltage stays around 0.3v.
Larger the loading, the larger the drop-out voltage. The voltage starts to drop below 3.3v at 4.2v input under 300ma loading. The drop out voltage lays around 0.9v to 1.3v.
Be aware that if you are using a battery-powered microcontroller, a sudden demand in power (such as wifi connection) might surge the current over 300ma which may trigger a brownout detection.