AP2139AK-3.3TRG1 from Diodes Incorporated, in a SOT-23-5. Pinout and pin descriptions extracted from the manufacturer datasheet by ds2sf; symbol, footprint, and 3D from KiCad-official CAD.

Pinout

Pin	Name	Type	Function
1	VIN	power_in	Input voltage supply. Recommended operating range 2.5V to 6.0V (absolute max 6.6V). Requires 1µF ceramic input capacitor.
2	GND	power_in	Device ground reference.
3	CE	input	Active-high chip enable input. Logic high = enable, logic low = shutdown (with active quick output discharge). VIH ≥ 1.2V, VIL ≤ 0.3V, internal ~0.2µA pull-down; absolute max -0.3V to VIN+0.3V.
4	NC	unconnected	No internal connection. May be left floating or tied to GND.
5	VOUT	power_out	Regulated 3.3V output, 250mA capable. Requires ≥1µF ceramic output capacitor (ESR 0.01Ω to 100Ω) for stability. ±2% output accuracy.

Key specifications

Parameter	Value
Manufacturer	Diodes Incorporated
Package	SOT-23-5
Category	PMIC
Pins	5

Ordering variants

Same part, different packaging or reel option.

AP2139AK-3.3TRG1

CAD (KiCad official)

Symbol: AP2139AK-3.3TRG1
Footprint: Package_TO_SOT_SMD:SOT-23-5
3D model: SOT-23-5 (KiCad packages3D, STEP)

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

Datasheet: Diodes Incorporated datasheet (29 pp, sha256 027e80492a5bc199, retrieved 2026-08-17, tier: manufacturer)
Extractor: ds2sf (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF