LM431CIM3 from Texas Instruments, in a SOT-23. Pinout and pin descriptions extracted from the manufacturer datasheet (extract_pins, cross-checked by a second model); symbol, footprint, and 3D from KiCad-official CAD.

Pinout

Pin	Name	Type	Function
1	Cathode	bidirectional	Cathode is the shunt current/output voltage pin, rated to 37 V maximum with continuous cathode current from -10 mA to 150 mA.
2	Reference	input	Reference pin sets the adjustable output voltage, with a reference voltage of -0.5 V minimum and a reference input current of 10 mA maximum.
3	Anode	output	Anode pin is normally grounded and is the shunt current return path.

Key specifications

Parameter	Value
Manufacturer	Texas Instruments
Package	SOT-23
Category	Power Management (PMIC)
Pins	3

Electrical characteristics

Limits as printed in the datasheet (page.json metadata.characteristics carries them as data).

Parameter	Symbol	Min	Typ	Max	Unit	Conditions	Page
Reference voltage	VREF	2.485	2.5	2.51	V	VZ = VREF, II = 10 mA (LM431C)	5
Deviation of reference input voltage overtemperature	VDEV		8	17	mV	VZ = VREF, II = 10 mA, TA = full range	5
Ratio of change in reference voltage to change in cathode voltage, VZ from VREF to 10 V	ΔVREF/ΔVZ		-1.4	-2.7	mV/V	IZ = 10 mA, VZ from VREF to 10 V	5
Ratio of change in reference voltage to change in cathode voltage, VZ from 10 V to 36 V	ΔVREF/ΔVZ		-1	-2	mV/V	IZ = 10 mA, VZ from 10 V to 36 V	5
Reference input current	IREF		2	4	μA	R1 = 10 kΩ, R2 = ∞, II = 10 mA	5
Deviation of reference input current overtemperature	∝IREF		0.4	1.2	μA	R1 = 10 kΩ, R2 = ∞, II = 10 mA, TA = full range	5
Minimum cathode current for regulation	IZ(MIN)		0.4	1	mA	VZ = VREF	5
OFF-state current	IZ(OFF)		0.3	1	μA	VZ = 36 V, VREF = 0 V	5
Dynamic output impedance (LM431C)	rZ			0.5	Ω	VZ = VREF, LM431B, LM431C, Frequency = 0 Hz	6
Average temperature coefficient				50	ppm/°C	Average Temperature Coefficient (feature list)	1
Cathode voltage	VZ			37	V		4
Reference voltage	VREF	-0.5			V		4
Continuous cathode current	IZ	-10		150	mA		4
Reference input current	IREF			10	mA		4
Internal power dissipation, SOT-23 package	PD			0.28	W	SOT-23 package, ambient at 25°C; derate 2.2 mW/°C above 25°C	4
Operating temperature, industrial (LM431xI)	TA	-40		85	°C	Industrial (LM431xI)	4
Storage temperature	TSTG	-65		150	°C		4
Cathode voltage operating range	VZ			37	V	Cathode voltage, lower limit VREF	4
Cathode current	IZ	1		100	mA		4
Junction-to-ambient thermal resistance, SOT-23	RθJA		267.7		°C/W	DBZ (SOT-23) package	4
Junction-to-case (top) thermal resistance, SOT-23	RθJC(top)		138.3		°C/W	DBZ (SOT-23) package	4
Junction-to-board thermal resistance, SOT-23	RθJB		61		°C/W	DBZ (SOT-23) package	4
Junction-to-top characterization parameter, SOT-23	ψJT		21.5		°C/W	DBZ (SOT-23) package	4
Junction-to-board characterization parameter, SOT-23	ψJB		60.1		°C/W	DBZ (SOT-23) package	4

CAD (KiCad official)

Symbol: LM431CIM3
Footprint: Package_TO_SOT_SMD:SOT-23
3D model: SOT-23 (KiCad packages3D, STEP)
3D model files: lm431cim3-etched.step / lm431cim3-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); lm431cim3.step / lm431cim3.glb are the bare package body.

Provenance

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

Datasheet: Texas Instruments datasheet (37 pp, sha256 9c0bcff4967eaad2, retrieved 2026-11-05, tier: manufacturer)
Extractor: parts-factory 2.0.0 / extract_pins 0.3, primary claude-haiku-5-5 (text), consensus claude-sonnet-5-5 (agreed), guards: pin_guards 0.1: passed. Pins are checked against the footprint pad set and their cited datasheet pages before publish.
CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF

LM431CIM3

Verified LM431CIM3

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3D Model

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Datasheet

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