What this source-sink power MUX does for your rail
The TPS66120YBGR is a single-channel source and sink power multiplexer from Texas Instruments, designed to steer power between two supply rails or to combine sourcing and sinking paths in a compact 28-DSBGA (1.61x2.81 mm) footprint.
Package and board-fit reality
Housed in a 28-ball XFBGA (DSBGA) with a 1.61x2.81 mm body, the part demands a fine-pitch BGA layout — the 0.4 mm ball pitch typical of this package class requires at least a 4-layer PCB with microvias for fan-out; a 2-layer board will struggle to route all signals. Surface-mount assembly with standard reflow profiles works, but the small body means solder-paste volume and stencil aperture need tight control to avoid bridging or opens on the BGA balls.