AP2138N-2.5TRG1 from Diodes Incorporated AP2138N 2 5TRG1, in a SOT-23-3. 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	GND	power_in	Ground reference for the regulator. Connect directly to the system ground plane.
2	VOUT	power_out	Regulated output voltage, fixed 2.5V ±2% (1.5% typ). Supplies up to 250mA. Requires a >1µF ceramic output capacitor (ESR 0.01Ω-100Ω) for stability.
3	VIN	power_in	Input supply voltage, 2.5V to 6.0V recommended (6.6V absolute max). Requires a 1µF ceramic input capacitor. Dropout ~700mV at 100mA load.

Key specifications

Parameter	Value
Manufacturer	Diodes Incorporated AP2138N 2 5TRG1
Package	SOT-23-3
Category	PMIC
Pins	3

Ordering variants

AP2138N-2.5TRG1
AP2138N-2.5TRG1AP2138R-2.5TRG1
AP2138N-2.5TRG1AP2138RA-2.5TRG1
AP2138N-2.5TRG1AP2139AK-2.5TRG1

CAD (KiCad official)

Symbol: AP2138N-2.5TRG1
Footprint: Package_TO_SOT_SMD:SOT-23-3
3D model: SOT-23-3 (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`ap2138n-2-5trg1.step`	59 KB	You want the bare part, or you mark your own boards.
`ap2138n-2-5trg1-etched.step`	2.4 MB	You want the part with `AP2138N-2.5TRG1` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 581 faces against 69 in the bare model. It survives export, section views, and rendering in any CAD tool, and it drops straight into KiCad or Fusion with no extra setup.

Provenance

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

Datasheet: Diodes Incorporated AP2138N 2 5TRG1 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