Fixed 1.8V rail for battery-powered portables
The ADP2139ACBZ-1.8-R7 is a synchronous buck regulator that delivers a fixed 1.8V output at up to 800mA from a 2.3V to 5.5V input rail — the sweet spot for single-cell Li-Ion or 3.3V/5V system buses powering a 1.8V core or I/O plane. The 3MHz switching frequency lets the output filter shrink to a small ceramic cap and a low-profile inductor — the whole supply fits in the 1.03x1.50mm WLCSP footprint, which is the point: this part is built for space-constrained portable gear where every mm² counts.
Synchronous rectification and thermal envelope
The integrated synchronous rectifier eliminates the external Schottky diode — the efficiency curve holds up at light loads because the low-side FET turns on instead of a diode forward drop. The 6-WLCSP package (1.03x1.50mm) routes the power and ground through the bump array — the PCB layout must keep the input cap within 2mm of the PVIN bump to avoid input ripple that triggers the overcurrent comparator on fast load steps. The datasheet layout recommendation is the safe starting point.
Availability and current pricing confirmed at RFQ time; no stock-holding claim on this listing.