MD8942 from Shanghai Mingda Microelectronics, in a SOT-23-6L. 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	BST	passive	Bootstrap pin providing gate-drive bias for the internal high-side switch FET. Connect a bootstrap capacitor (Cboot) between BST and SW. Absolute max BST-to-SW voltage is 6V; internally charged to ~5V from VCB through a diode.
2	GND	power_in	Device ground connection. Should be connected as close as possible to the output capacitor to avoid high current switching paths and to serve as the reference for feedback and enable.
3	FB	input	Feedback input to the internal error amplifier. Set the output voltage via a resistor divider from VOUT to FB using VOUT = VFB × (1 + R2/R1), where VFB is typically 0.794V. Absolute max -0.3V to 6V.
4	EN	input	Enable input, active-high logic. Pulling EN above the ~1V rising threshold enables the chip; pulling below the falling threshold (~0.84V, 160mV hysteresis) shuts it down. Floating EN disables the chip (internal 430kΩ pull-down to GND). Internal zener clamps EN to ~5V, absolute max 6V, sink current limit 100µA.
5	VIN	power_in	Input supply pin. Operating range 4V to 36V, standoff input voltage 42V. Bypass with a low-ESR ceramic input capacitor (typ. 10µF) placed as close as possible to VIN and GND.
6	SW	output	Switch node - the output of the internal high-side and low-side power MOSFETs. Connect to the external inductor and to the bootstrap capacitor's low side. Absolute max -0.3V to VIN(MAX)+0.3V.

Key specifications

Parameter	Value
Manufacturer	Shanghai Mingda Microelectronics
Package	SOT-23-6L
Category	PMIC
Pins	6

CAD (KiCad official)

Symbol: MD8942
Footprint: Package_TO_SOT_SMD:SOT-23-6
3D model: SOT-23-6L (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`md8942.step`	97 KB	You want the bare part, or you mark your own boards.
`md8942-etched.step`	1.5 MB	You want the part with `MD8942` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 360 faces against 117 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: Shanghai Mingda Microelectronics datasheet (13 pp, sha256 758503482648cacf, retrieved 2026-08-17, tier: lcsc)
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