SM5101B from HICHON, in a SOP-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	OUT	output	Heater-drive output. Sources the load current to the heating coil; internal switch RDS(on) ≈ 95 mΩ. Short-circuit protection trips at IOCP ≈ 4.3 A (VBAT=3.7V) and shuts off with loads below 0.8 Ω.
2	BAT	power_in	Battery positive terminal (single-cell Li-ion). Absolute max -0.3 V to +4.5 V. Sources up to 250 mA discharge current (2.7 V ≤ VBAT ≤ 4.1 V); charge terminates when VBAT reaches 4.20 V float and current drops below 1/10 setpoint; auto-recharge below 4.05 V.
3	LED1	output	Charge-status and output-status indicator LED driver. On during charging; blinks 20 times (2 Hz, 50% DC) when charge completes. During touch-on the pin ramps up (~1 s), stays lit ~8 s, then blinks twice before OUT closes. Nominal ILED ≈ 15 mA.
4	LED2	output	EN operating-state indicator LED driver. Solid on when EN is tied to GND (touch enabled); off when EN floats. Nominal ILED ≈ 15 mA.
5	GND	power_in	Chip ground reference. Common return for VDD, BAT, OUT and all logic pins.
6	VDD	power_in	USB charger input (5 V nominal). Operating range 0.5 V to 5 V; absolute max -0.3 V to +5.5 V. UVLO rising threshold 3.4-3.8 V (typ 3.6 V) enables the charge cycle; supply for internal charger and touch/LED logic.
7	T	input	Touch-sense input. Connects to the exposed touch pad; sensitivity adjustable by a small parallel capacitor Cs (1 pF ≤ Cs ≤ 50 pF) - no cap = maximum sensitivity, larger Cs reduces sensitivity. Active only when EN=GND and VBAT>3.2 V.
8	EN	input	Touch-switch enable input with internal 100 kΩ pull-up. Tie to GND (through switch S1) to enable touch detection; leave floating (pull-up) to disable and put the chip into sleep. Absolute max -0.3 V to +5.5 V.

Key specifications

Parameter	Value
Manufacturer	HICHON
Package	SOP-8
Category	Sensor
Pins	8

CAD (KiCad official)

Symbol: SM5101B
Footprint: Package_SO:SOIC-8_3.9x4.9mm_P1.27mm
3D model: SOP-8 (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`sm5101b.step`	122 KB	You want the bare part, or you mark your own boards.
`sm5101b-etched.step`	1.7 MB	You want the part with `SM5101B` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 426 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: HICHON datasheet (7 pp, sha256 db62c507b07b0b51, 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