# TL431CDR

**Texas Instruments** · Voltage Reference · SOIC-8

TL431CDR from Texas Instruments, in a SOIC-8. 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 | output | Output terminal supporting 1 to 100 mA continuous shunt current sink with programmable voltage from Vref (approximately 2.5V) to 36V and 0.2Ω typical output impedance. |
| 2 | ANODE | power_in | Common ground return pin for regulator; must be connected to system ground with all other ANODE pins for proper current distribution. |
| 3 | ANODE | power_in | Common ground return pin for regulator; must be connected to system ground with all other ANODE pins for proper current distribution. |
| 4 | NC | unconnected | No internal connection; leave unconnected per datasheet specifications. |
| 5 | NC | unconnected | No internal connection; leave unconnected per datasheet specifications. |
| 6 | ANODE | power_in | Common ground return pin for regulator; must be connected to system ground with all other ANODE pins for proper current distribution. |
| 7 | ANODE | power_in | Common ground return pin for regulator; must be connected to system ground with all other ANODE pins for proper current distribution. |
| 8 | REF | input | Reference input pin with nominal threshold of 2.495V requiring 2 to 4 µA input current for linear operation as feedback node to set regulator output voltage. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Texas Instruments |
| Package | SOIC-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 | Vref | 2440 | 2495 | 2550 | mV | VKA = Vref, IKA = 10mA | 6 |
| Deviation of reference input voltage over full temperature range (All other devices) | VI(dev) |  | 4 | 25 | mV | VKA = Vref, IKA = 10mA; All other devices | 6 |
| Ratio of change in reference voltage to change in cathode voltage | ΔVref / ΔVKA |  | -1.4 | -2.7 | mV/V | IKA = 10mA, ΔVKA = 10V - Vref | 6 |
| Ratio of change in reference voltage to change in cathode voltage | ΔVref / ΔVKA |  | -1 | -2 | mV/V | IKA = 10mA, ΔVKA = 36V - 10V | 6 |
| Reference Input Current | Iref |  | 2 | 4 | µA | IKA = 10mA, R1 = 10kΩ, R2 = ∞ | 6 |
| Deviation of reference input current over full temperature range | II(dev) |  | 0.4 | 1.2 | µA | IKA = 10mA, R1 = 10kΩ, R2 = ∞ | 6 |
| Minimum cathode current for regulation | Imin |  | 0.4 | 1 | mA | VKA = Vref | 6 |
| Off-state cathode current | Ioff |  | 0.1 | 1 | µA | VKA = 36V, Vref = 0 | 6 |
| Dynamic Impedance | /ZKA/ |  | 0.2 | 0.5 | Ω | VKA = Vref, f ≤ 1kHz, IKA = 1mA to 100mA | 6 |
| Cathode Voltage | VKA |  |  | 37 | V |  | 5 |
| Continuous Cathode Current Range | IKA | -100 |  | 150 | mA |  | 5 |
| Reference Input Current | II(ref) | -0.05 |  | 10 | mA |  | 5 |
| Operating Junction Temperature Range | TJ |  |  | 150 | °C |  | 5 |
| Storage Temperature Range | Tstg | -65 |  | 150 | °C |  | 5 |
| Cathode Voltage | VKA |  |  | 36 | V |  | 5 |
| Continuous Cathode Current Range | IKA | 1 |  | 100 | mA |  | 5 |
| Operating Free-Air Temperature | TA | 0 |  | 70 | °C | TL43xxC | 5 |
| Junction-to-ambient thermal resistance (D package, 8 pins) | RθJA |  | 97 |  | °C/W | D (SOIC, 8 pins) | 5 |
| Junction-to-case (top) thermal resistance (D package, 8 pins) | RθJC(top) |  | 39 |  | °C/W | D (SOIC, 8 pins) | 5 |

## CAD (KiCad official)

- Symbol: `TL431CDR`
- Footprint: `Package_SO:SOIC-8_3.9x4.9mm_P1.27mm`
- 3D model: SOIC-8 (KiCad packages3D, STEP)
- 3D model files: `tl431cdr-etched.step` / `tl431cdr-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `tl431cdr.step` / `tl431cdr.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/lit/ds/symlink/tl431c.pdf) (85 pp, sha256 `ed2e90697de4e2c5`, retrieved 2026-09-22, tier: manufacturer)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.2`, primary `claude-haiku-4-5-20251001` (text), consensus `claude-sonnet-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/tl431cdr-datasheet.pdf)