In this MP2162 buck regulator, L1 is the power inductor of the switching power stage.
What it does:
Stores energy when U1’s SW switch turns on, then releases that energy to the output when the switch turns off.
Together with the output capacitor C1, it filters the switching waveform at SW into a steady DC output on Net 4 (+1V2).
Sets the inductor ripple current and affects transient response and efficiency.
How it’s connected here:
L1.P1 is tied to U1 SW on Net 5 (the switching node).
L1.P2 goes to Net 4, which is the regulated output rail (+1V2), shared with U1 OUT, C1, and the sense network via R1/R2.
Notable property:
Inductance: 1 µH (as set on L1), which is typical for high-frequency, low-voltage buck converters like the MP2162 to balance ripple current and transient performance.
In short: L1 is the main energy storage/filter element that converts the SW node’s pulsed voltage into the smooth +1.2 V output.