HG811SM4 from HGSEMI, in a SOT-143-4. 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 / negative supply return for the reset detector. Tie to system ground.
2	VRESET	output	Active-low reset output. Driven low (VOL <= 0.5 V @ ISINK=3.2 mA) whenever VCC < Vth (2.93 V for HG811SM4) or MR is held low; released to a push-pull high (>=0.8*VCC @ ISOURCE=500 µA) after the Trp reset delay (~500 ms typ) once VCC recovers and MR is released.
3	MR	input	Active-low manual-reset / enable input. VMRL <= 0.2VCC forces VRESET low; VMRH >= 0.7VCC allows normal operation. Minimum recognized low-pulse width tMR = 10 µs. Input pull current IMR up to 25 µA @ VCC=6 V.
4	VCC	power_in	Positive supply and monitored rail. Operating range 1.0 V to 6.0 V (absolute max 6.5 V). Quiescent current ICCH ~1-5 µA when MR=VCC; ICCL up to 32 µA when MR=GND.

Key specifications

Parameter	Value
Manufacturer	HGSEMI
Package	SOT-143-4
Category	PMIC
Pins	4

Ordering variants

Same part, different packaging or reel option.

HG811SM4/TR

CAD (KiCad official)

Symbol: HG811SM4
Footprint: Package_TO_SOT_SMD:SOT-143
3D model: SOT-143-4 (KiCad packages3D, STEP)

Provenance

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

Datasheet: HGSEMI datasheet (7 pp, sha256 a75fd3d5b03be350, 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