When the MP2760 is operated without a battery connected, the SYS output becomes highly unstable. Even under very light load, the SYS voltage collapses sharply (down to approximately ~2 V) and then recovers. Under no-load conditions, SYS oscillates between its nominal voltage and lower levels.
The input voltage remains stable. While the system operates stably with the battery connected, severe SYS voltage sag occurs under even minimal load when operating without a battery. Below is the VSYS waveform measured under a 500 mA load.
