component
TL431
Public Unreviewedby adom
TI adjustable precision shunt regulator, SOT-23. Vref 2.5 V, programmable to 36 V, sinks 1-100 mA. Datasheet-verified.
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README.md+43−2@@ -1,5 +1,46 @@ # TL431 -Programmable precision voltage reference, SOT-23 / TO-92+**Texas Instruments** · Adjustable shunt voltage reference · SOT-23 (DBZ) -The TL431 is a programmable shunt voltage reference from TI. Adjustable from 2.5V to 36V with 0.5% initial accuracy. Used in power supply feedback circuits, voltage references, and current limiters.+Three-terminal adjustable precision shunt regulator, a programmable Zener, in a SOT-23 package. A resistor divider from the cathode to REF sets the shunt voltage anywhere from the 2.5 V internal reference up to 36 V. It sinks 1-100 mA with ~0.2 ohm output impedance. The default feedback reference for switching supplies and adjustable linear regulators, and a precise Zener replacement. Wire REF to the divider tap, cathode to the node being regulated, anode to ground.++## Pinout++| Pin | Name | Type | Function |+|---|---|---|---|+| 1 | K | passive | Shunt cathode (K). Current-sink terminal referenced to ANODE; V(KA) may range from Vref (~2.5 V) up to the absolute-max 37 V. Continuous cathode current I(KA) = 1 mA to 100 mA in normal operation (abs-max −100 to 150 mA). Sinks current when V(REF-ANODE) exceeds Vref, regulating V(KA) at the value set by the external divider. |+| 2 | REF | input | Reference (feedback) input, threshold relative to ANODE. Internal error amp regulates V(REF) to Vref (~2.5 V nominal, 0.5%/1%/2% grades). Reference input current I(ref) is very small (abs-max −0.05 to 10 mA); typically driven from a resistor divider between CATHODE and ANODE to program V(KA) = Vref × (1 + R1/R2) + I(ref)·R1. |+| 3 | A | passive | Common return terminal (A), normally connected to circuit ground. All device voltages (V(KA), V(REF)) are referenced to ANODE. Carries the sum of cathode sink current and reference-input current. |++## Key specifications++| Parameter | Value |+|---|---|+| Type | Adjustable shunt voltage reference |+| Reference voltage (Vref) | 2.5 V (typ 2.495 V) |+| Output range | Vref to 36 V (external divider) |+| Cathode current | 1 mA to 100 mA |+| Output impedance | 0.2 Ω typ |+| Package | SOT-23 (DBZ) |+| Body (L×W×H) | 2.9 × 1.3 × 1.1 mm |++## Ordering variants++- `TL431AIDBZR (SOT-23, ±0.5%)`+- `TL431BIDBZR (SOT-23, ±0.5%, tighter tempco)`++## CAD (KiCad official)++- Symbol: `Reference_Voltage:TL431DBZ`+- Footprint: `Package_TO_SOT_SMD:SOT-23`+- 3D model: SOT-23 (KiCad packages3D)++## Provenance++Data extracted from the manufacturer datasheet, not a distributor listing:++- **Datasheet:** [Texas Instruments datasheet](https://www.ti.com/lit/ds/symlink/tl431.pdf) (85 pp, sha256 `49d4bc6e1bdcfab7`, retrieved 2026-08-17, tier: manufacturer)+- **Extractor:** `ds2sf` (Claude) — every pin and dimension is cited to a datasheet page; refuses to fabricate.+- **CAD:** KiCad official libraries (CC-BY-SA 4.0).++[Datasheet PDF](docs/tl431-datasheet.pdf)
docs/tl431-datasheet.pdfadded⋯ 1 unchanged line ⋯
package.jsonadded+30@@ -0,0 +1,30 @@+{+ "slug": "tl431",+ "version": "0.1.0",+ "type": "component",+ "description": "TI adjustable precision shunt regulator, SOT-23. Vref 2.5 V, programmable to 36 V, sinks 1-100 mA. Datasheet-verified.",+ "tags": [+ "component",+ "voltage-reference",+ "shunt-regulator",+ "tl431",+ "sot-23",+ "texas-instruments"+ ],+ "dependencies": {},+ "hero": {+ "type": "image",+ "path": "docs/hero.png"+ },+ "files": [+ "page.json",+ "README.md",+ "tl431.kicad_sym",+ "tl431.kicad_mod",+ "tl431.glb",+ "docs/hero.png",+ "docs/tl431-datasheet.pdf",+ "viewers/symbol.html",+ "viewers/footprint.html"+ ]+}
page.json+27−7@@ -4,8 +4,15 @@ "slug": "tl431", "title": "TL431", "brief": "Programmable precision voltage reference, SOT-23 / TO-92",- "version": "1.0.0",- "tags": [],+ "version": "0.1.0",+ "tags": [+ "component",+ "voltage-reference",+ "shunt-regulator",+ "tl431",+ "sot-23",+ "texas-instruments"+ ], "license": "MIT", "component": { "mpn": "TL431",@@ -20,18 +27,31 @@ }, "readme": "# TL431\n\nProgrammable precision voltage reference, SOT-23 / TO-92\n\nThe TL431 is a programmable shunt voltage reference from TI. Adjustable from 2.5V to 36V with 0.5% initial accuracy. Used in power supply feedback circuits, voltage references, and current limiters.", "author": {- "id": "695820315b5f1e4db2fcf602", "name": "Kyle Bergstedt", "email": "[email protected]" },- "visibility": {- "public": true+ "visibility": "public",+ "hero": {+ "type": "image",+ "path": "docs/hero.png" },- "hero": null, "sample_prompts": [], "discovery_triggers": [], "discovery_pitch": null, "metadata": {}, "created_at": "2026-05-28T05:34:20.354Z",- "updated_at": "2026-05-28T05:34:20.354Z"+ "updated_at": "2026-05-28T05:34:20.354Z",+ "description": "TI adjustable precision shunt regulator, SOT-23. Vref 2.5 V, programmable to 36 V, sinks 1-100 mA. Datasheet-verified.",+ "dependencies": {},+ "files": [+ "page.json",+ "README.md",+ "tl431.kicad_sym",+ "tl431.kicad_mod",+ "tl431.glb",+ "docs/hero.png",+ "docs/tl431-datasheet.pdf",+ "viewers/symbol.html",+ "viewers/footprint.html"+ ] }
tl431.glbadded⋯ 1 unchanged line ⋯
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