AP1538SG-13 from Diodes Incorporated, in a SOIC-8. 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	FB	input	Feedback pin. Connect to the resistor divider from VOUT to set the regulated output voltage using VOUT = VFB x (1 + RA/RB), with VFB typically 0.8V.
2	EN	input	Enable (power-off) pin. Drive High (>=2.0V) for normal step-down operation; drive Low (<=0.8V) to stop step-down operation and deactivate all internal circuits.
3	OCSET	input	Over-current set pin. Connect an external resistor (typically ~3kΩ) to set the maximum output current limit; internal bias current ~90µA.
4	VCC	power_in	IC power supply input. Operating range 3.6V to 18V; bypass locally with a decoupling capacitor (0.1µF typ) plus bulk input cap (e.g. 470µF).
5	Output	output	Switch node output (drain of the internal P-channel power MOSFET). Connect the external inductor and freewheel Schottky diode here; minimize trace area to reduce EMI. Pin 5 is tied internally to pin 6.
6	Output	output	Switch node output (drain of the internal P-channel power MOSFET). Connect the external inductor and freewheel Schottky diode here; minimize trace area to reduce EMI. Pin 6 is tied internally to pin 5.
7	Vss	power_in	Ground return. Pin 7 is tied internally to pin 8 and should be connected to the system ground plane.
8	Vss	power_in	Ground return. Pin 8 is tied internally to pin 7 and should be connected to the system ground plane.

Key specifications

Parameter	Value
Manufacturer	Diodes Incorporated
Package	SOIC-8
Category	PMIC
Pins	8

Ordering variants

AP1538SG-13
AP1538SG-13SDPG-13

CAD (KiCad official)

Symbol: AP1538SG-13
Footprint: Package_SO:SOIC-8_3.9x4.9mm_P1.27mm
3D model: SOIC-8 (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`ap1538sg-13.step`	122 KB	You want the bare part, or you mark your own boards.
`ap1538sg-13-etched.step`	2.5 MB	You want the part with `AP1538SG-13` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 598 faces against 147 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 datasheet (12 pp, sha256 638a3ccf88cbfdca, 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