AP2900TB-A1 from Wuxi Chipown Micro electronics, in a SOT-23-5L. 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 supply voltage, 6 V to 40 V operating (42 V absolute max). Requires a low-ESR decoupling capacitor (1 uF X5R/X7R MLCC in parallel with a 100 uF electrolytic recommended) placed as close as possible between VIN and GND to supply AC current to the internal power MOSFETs.
2	GND	power_in	Ground pin. Common return for internal control circuitry and the low-side synchronous MOSFET source. Recommended to connect to the ground copper plane via vias for good thermal dissipation and noise suppression.
3	EN	input	Enable input. High level enables the IC, low level disables the IC (shutdown mode). Must not be tied directly to VIN, and must not be connected to VIN through a series resistor. Drive voltage must be kept below 5 V. Internally pulled up by an approximate 50 uA current source to ~4.5 V, so the IC auto-starts if EN is left floating. If an external pull-down resistor is used to disable, it must be < 4.7 kΩ to guarantee a valid low.
4	FB	input	Feedback input. Connect to the midpoint of the external output feedback divider to program the output voltage (VFB reference 1.2 V typ). Route away from the SW switching node to minimize noise pickup.
5	SW	output	Switch node. Drain of the internal high-side P-MOSFET and source of the low-side N-MOSFET; connect to the external inductor with a short, wide, thick trace to minimize EMI and switching loss.

Key specifications

Parameter	Value
Manufacturer	Wuxi Chipown Micro electronics
Package	SOT-23-5L
Category	PMIC
Pins	5

Ordering variants

AP2900TB-A1

CAD (KiCad official)

Symbol: AP2900TB-A1
Footprint: Package_TO_SOT_SMD:SOT-23-5
3D model: SOT-23-5L (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`ap2900tb-a1.step`	85 KB	You want the bare part, or you mark your own boards.
`ap2900tb-a1-etched.step`	2.0 MB	You want the part with `AP2900TB-A1` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 491 faces against 102 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: Wuxi Chipown Micro electronics datasheet (14 pp, sha256 c213c0743d731535, retrieved 2026-08-17, tier: lcsc)
Datasheet language: Chinese. Pin names, descriptions, and specs on this page were extracted and translated to English by ds2sf; the linked PDF is the manufacturer original.
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