# TL431BQDBZR

**Texas Instruments** · Voltage Reference · SOT-23-3

TL431BQDBZR from Texas Instruments, in a SOT-23-3. 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 | CATHODE | passive | Shunt cathode (K). Shunt current/voltage input; connects to the load via a series resistor. Sinks 1 mA to 100 mA when regulating; cathode voltage is set by the divider that drives REF to Vref (~2.5 V). |
| 2 | REF | input | Reference input to the internal error amplifier. Compared against the internal ~2.5 V bandgap reference; connect to the tap of the external resistor divider from CATHODE to ANODE to program the regulated cathode voltage. |
| 3 | ANODE | passive | Shunt anode (A). Common return, normally tied to circuit ground. |

## Key specifications

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

## Ordering variants

Same part, different packaging or reel option.

- `TL431BQDBZR`
- `TL431BQDBZRDBZT`
- `TL431BQDBZRDBVR`
- `TL431BQDBZRDBVT`
- `TL431BQDBZRDR`
- `TL431BQDBZRD`
- `TL431BQDBZRP`
- `TL431BQDBZRPS`
- `TL431BQDBZRPWR`
- `TL431BQDBZRPW`
- `TL431BQDBZRLP`
- `TL431BQDBZRLPR`
- `TL431BQDBZRLPM`
- `TL431BQDBZRDCKR`
- `TL431BQDBZRDCKT`
- `TL431BQDBZRPK`

## CAD (KiCad official)

- Symbol: `TL431BQDBZR`
- Footprint: `Package_TO_SOT_SMD:SOT-23-3`
- 3D model: SOT-23-3 (KiCad packages3D, STEP)
- 3D model files: `tl431bqdbzr-etched.step` / `tl431bqdbzr-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `tl431bqdbzr.step` / `tl431bqdbzr.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Texas Instruments datasheet](https://www.ti.com/cn/lit/gpn/tl431) (86 pp, sha256 `0eb18c491f5517a3`, 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](docs/tl431bqdbzr-datasheet.pdf)