PW2058 - Low-power lithium battery 3.7V to 3V reduction solution

The image above is the second version of the 3D simulation; the main image is the first version. The module is very compact, measuring 16mm x 16mm.
 
It uses the PW2058 chip, which can step down the lithium battery voltage to 3.3V, 3V, or 1.5V, making it suitable for low-power, long-lasting applications, such as DIY modifications. If used for converting a gas stove to a lithium battery, the wiring needs to be routed to keep the lithium battery away from the gas stove; otherwise, the lithium battery may overheat and catch fire.
 
The module's battery-side quiescent current is only 40µA, the module's conversion efficiency is no less than 85%, and the maximum output current is 800mA. It can operate continuously at 400mA when converting a lithium battery to 3V. This is thanks to the PW2058's extremely low quiescent current and high conversion efficiency.
 
The photo shows the first version of this module, which lacks a DSS14 Schottky diode. During testing, the PW2058 burned out due to reverse battery connection. Therefore, a diode was added for foolproof protection. At 400mA output, the voltage drop is approximately 0.36V. In a lithium battery step-down circuit, the energy loss is about 8% of the total. If not needed, two pins can be shorted, but note that the battery must not be reversed!
 
The attached file contains PCB fabrication instructions for direct board fabrication. Component list:
PW2058 1 x
10uf, 0805 3
x 100nf, 0805 1 x
22pf, 0805 1 x
2.2uH, 0420 1 x
100kΩ, 0805 1 x,
DSS14 1 x. This component is mainly for preventing reverse battery connection; it is optional and can be replaced with an SS14 or any Schottky diode with a withstand voltage of 10V or higher and a current rating of at least 1A. Note that the voltage drop must be low.
RADJ Resistors:
453kΩ 0805 (1 piece, 3.3V output),
390kΩ 0805 (1 piece, 3V output),
150kΩ 0805 (1 piece, 1.5V output).
0603 capacitors can also be used; they can all be soldered. The inductor must be 0420; I bought the wrong one (the one in the photo is 0630), which is too large and can barely be soldered, but very difficult. The RADJ resistor needs to be selected according to the output voltage, as clearly stated above.
 
Note 1: This module does not have a battery protection circuit. If the lithium battery used does not have a protection board, a protection board needs to be connected to the lithium battery.
Note 2: It seems that the quality of the purchased PW2058 chips varies. One chip had a static current of several hundred microamps after powering on and was unstable. When troubleshooting, the PW2058 was swapped to another board that tested without problems, and the same issue occurred on that board. Therefore, it is suspected that the chip is the problem. After soldering, it is best to use a multimeter to test the static current at the battery terminal. It should normally be between 30-50uA.