# TL431AQDBZT

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

TL431AQDBZT 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 regulator cathode (K). Sinks 1-100 mA of cathode current when REF exceeds Vref (~2.5 V) - absolute-max continuous IKA = -100 to +150 mA, VKA(max) = 37 V, VKA(recommended) = Vref to 36 V. Output dynamic impedance is typ 0.2 Ω. |
| 2 | REF | input | Reference (feedback) input, threshold relative to ANODE. Internal comparator drives the shunt on when V(REF) ≥ Vref (nominal 2.5 V). Reference input current range -0.05 mA to +10 mA (absolute max); tie to divider tap between CATHODE and ANODE to program the regulated voltage. |
| 3 | ANODE | power_in | Common anode / return terminal - the reference point for VKA and Vref. Tie to system ground in the standard shunt-regulator topology. |

## 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.

- `TL431AQDBZT`
- `TL431AQDBZTDBZR`
- `TL431AQDBZTDBVT`
- `TL431AQDBZTDBVR`
- `TL431AQDBZTPK`
- `TL431AQDBZTD`
- `TL431AQDBZTP`
- `TL431AQDBZTPS`
- `TL431AQDBZTPW`

## CAD (KiCad official)

- Symbol: `TL431AQDBZT`
- Footprint: `Package_TO_SOT_SMD:SOT-23-3`
- 3D model: SOT-23-3 (KiCad packages3D, STEP)
- 3D model files: `tl431aqdbzt-etched.step` / `tl431aqdbzt-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `tl431aqdbzt.step` / `tl431aqdbzt.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) (None 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/tl431aqdbzt-datasheet.pdf)