# LM431BIM

**HGSEMI** · Voltage Regulators - Linear, Low Drop Out (LDO) Regulators · SOP-8

LM431BIM from HGSEMI, in a SOP-8. 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 | passive | Cathode (K) of the shunt regulator; output terminal, adjustable from Vref (about 2.5V) up to 36V, with an absolute maximum VKA of 37V and IKA up to 150mA continuous. |
| 2 | ANODE | passive | Anode (A) of the shunt regulator, connected to the most negative supply/ground potential. |
| 3 | ANODE | passive | Anode (A) of the shunt regulator, connected to the most negative supply/ground potential. |
| 4 | NC | unconnected | No connection. |
| 5 | NC | unconnected | No connection. |
| 6 | ANODE | passive | Anode (A) of the shunt regulator, connected to the most negative supply/ground potential. |
| 7 | ANODE | passive | Anode (A) of the shunt regulator, connected to the most negative supply/ground potential. |
| 8 | REF | input | Reference input of the shunt regulator with nominal Vref of 2.495V (LM431B: 2.470V to 2.520V) and reference input current up to 10mA absolute maximum. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | HGSEMI |
| Package | SOP-8 |
| Category | Power Management (PMIC) |
| Pins | 8 |

## 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 (LM431B) | VREF | 2.47 | 2.495 | 2.52 | V | VKA=VREF, IKA=10mA | 4 |
| Dynamic impedance | ZKA |  | 0.2 | 0.5 | Ω | VKA=VREF, IKA=1 to 100mA, f≤1.0KHz | 4 |
| Off-state cathode current | IKA (Off) |  | 0.1 | 1 | μA | VKA=36V, VREF=0V | 4 |
| Reference input current | IREF |  | 1.5 | 4 | μA | IKA=10mA, R1=10KΩ, R2=∞ | 4 |
| Minimum cathode current for regulation | IKA (Min) |  |  | 1 | mA | VKA =VREF - 0.4 | 4 |
| Cathode-anode voltage | VKA |  |  | 37 | V |  | 3 |
| Cathode current range (continuous) | IKA |  |  | 150 | mA |  | 3 |
| Reference input current range | IREF |  |  | 10 | mA |  | 3 |
| Allowable maximum power dissipation | PD |  |  | 770 | mW | SOP-8 package | 3 |
| Operating junction temperature | TJ |  |  | 150 | ℃ |  | 3 |
| Storage temperature range | TSTG | -65 |  | 150 | ℃ |  | 3 |
| Lead temperature (soldering) | TLEAD |  |  | 260 | ℃ | 10s soldering | 3 |
| Operating temperature range | TA | -40 |  | 85 | ℃ | LM431xI (industrial grade; LM431BI) | 3 |

## CAD (KiCad official)

- Symbol: `LM431BIM`
- Footprint: `Package_SO:SOIC-8_3.9x4.9mm_P1.27mm`
- 3D model: SOP-8 (KiCad packages3D, STEP)
- 3D model files: `lm431bim-etched.step` / `lm431bim-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `lm431bim.step` / `lm431bim.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [HGSEMI datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8770707402721107968) (9 pp, sha256 `7e234b72ffe30494`, retrieved 2026-10-18, 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:** 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/lm431bim-datasheet.pdf)