# TL431S

**UMW** · Voltage Reference · SOT-89-3

TL431S from UMW, in a SOT-89-3. 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 | REF | input | Reference input that sets the output voltage via an external resistor divider; reference input current range is 0.05 to 10 mA (absolute maximum). |
| 2 | ANODE | power_in | Anode terminal, connected to ground in typical shunt regulator circuits. |
| 3 | CATHODE | passive | Cathode terminal that sinks 0.5 mA to 100 mA recommended and up to 36 V recommended (40 V absolute maximum VKA). |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | UMW |
| Package | SOT-89-3 |
| 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 |
|---|---|---|---|---|---|---|---|
| Cathode Voltage | VKA |  |  | 40 | V |  | 2 |
| Cathode Current Range (Continuous) | IK | -100 |  | 150 | mA |  | 2 |
| Reference Input Current Range | IREF | 0.05 |  | 10 | mA |  | 2 |
| Operating Temperature Range | Toper. | -40 |  | 85 | °C |  | 2 |
| Junction Temperature Range | TJ |  |  | 150 | °C |  | 2 |
| Storage Temperature Range | TSTG | -65 |  | 150 | °C |  | 2 |
| Cathode Voltage | VKA |  |  | 36 | V |  | 2 |
| Cathode Current | IK | 0.5 |  | 100 | mA |  | 2 |
| Reference Input Voltage (0.5% grade) | VREF | 2.483 | 2.495 | 2.508 | V | TA=25°C, VKA=VREF, IK=10mA | 3 |
| Deviation of Reference Input Voltage Over Full Temperature Range | VREF(dev) |  | 3 | 17 | mV | Tmin≤Ta≤Tmax | 3 |
| Reference Input Current | IREF |  | 2 | 4 | µA | R1=10KΩ, R2=∞ | 3 |
| Deviation of Reference Input Current Over Full Temperature Range | IREF(dev) |  | 0.4 | 1.2 | µA | Tmin≤Ta≤Tmax, R1=10KΩ, R2=∞ | 3 |
| Dynamic Impedance | ZKA |  | 0.27 |  | Ω | IK=1mA to 100mA, f≤1.0KHz | 3 |
| Thermal Resistance From Junction to Ambient in Free Air (SOT-89) | θJA |  | 400 |  | °C/W | Free air, component mounted on high effective thermal conductivity test board | 2 |

## CAD (KiCad official)

- Symbol: `TL431S`
- Footprint: `Package_TO_SOT_SMD:SOT-89-3`
- 3D model: SOT-89-3 (KiCad packages3D, STEP)
- 3D model files: `tl431s-etched.step` / `tl431s-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `tl431s.step` / `tl431s.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [UMW datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8757111679618289664) (11 pp, sha256 `7c8052c62fb0f6ba`, retrieved 2026-10-09, tier: lcsc)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-sonnet-5-5` (text+vision), consensus `claude-opus-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](docs/tl431s-datasheet.pdf)