JSM421 from JSMSEMI, in a SOT-23. 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	VSUP	power_in	Supply voltage input. Operating range 3.8 V to 40 V (absolute max -60 V to +60 V). Typical supply current 6 mA (max 9 mA at VSUP = 5 V). Includes reverse-voltage protection.
2	GND	power_in	Ground / device return.
3	VOUT	output	Open-collector Hall-switch output; requires an external pull-up resistor (typ RL = 4.7 kΩ). Sinks up to 30 mA (abs max 40 mA), Vsat ≤ 0.4 V at Iout = 20 mA. Output leakage ≤ 10 µA. Absolute max output voltage -0.5 V to 60 V.

Key specifications

Parameter	Value
Manufacturer	JSMSEMI
Package	SOT-23
Category	Sensor
Pins	3

Ordering variants

Same part, different packaging or reel option.

JSM421 SOT23
JSM421 TO92S

CAD (KiCad official)

Symbol: JSM421
Footprint: Package_TO_SOT_SMD:SOT-23
3D model: SOT-23 (KiCad packages3D, STEP)

Provenance

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

Datasheet: JSMSEMI datasheet (8 pp, sha256 475d9cfb89c0da81, 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