# CD431A

**DOWO** · Voltage References · SOT-23

CD431A from DOWO, in a SOT-23. 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 (K) | passive | Cathode is rated up to 37 V (absolute maximum VKA) with a continuous cathode current range of 1 to 100 mA under recommended operating conditions. |
| 2 | Reference (R) | input | Reference input sets the internal 2.495 V typical reference voltage (VREF), with reference input current IREF of 1.5 µA typical and 4 µA maximum. |
| 3 | Anode (A) | passive | Anode is the return path for cathode current; the minimum cathode current for regulation IKA(MIN) is 1 mA maximum, with a 1.0 mA minimum sink current capability stated in the features. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | DOWO |
| Package | SOT-23 |
| Category | Power Management |
| Pins | 3 |

## 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 Input Voltage (CD431A, 0.5%) | VREF | 2.483 | 2.495 | 2.507 | V | VKA=VREF, IKA=10mA; Fig1 | 2 |
| Deviation of Reference Input Voltage Over Temperature | ΔVREF |  | 4.5 | 17 | mV | VKA=VREF, IKA=10mA, -25°C ≤TA≤+85°C; Fig1 | 2 |
| Ratio of Change in Reference Input Voltage to Change in Cathode Voltage (10V to VREF) |  |  | -1 | -2.7 | mV/V | IKA=10mA, ΔVKA=10V~VREF; Fig2 | 2 |
| Ratio of Change in Reference Input Voltage to Change in Cathode Voltage (36V to 10V) |  |  | -0.5 | -2 | mV/V | IKA=10mA, ΔVKA=36V~10V; Fig2 | 2 |
| Reference Input Current | IREF |  | 1.5 | 4 | µA | IKA=10mA, R1=10KΩ, R2=∞; Fig2 | 2 |
| Deviation of Reference Input Current Over Full Temperature Range | ΔIREF |  | 0.4 | 1.2 | µA | IKA=10mA, R1=10KΩ, R2=∞, -25°C ≤TA≤+85°C; Fig2 | 2 |
| Minimum Cathode Current for Regulation | IKA(MIN) |  | 0.45 | 1 | mA | VKA=VREF; Fig1 | 2 |
| Off-State Cathode Current | IKA(OFF) |  | 0.05 | 1 | µA | VKA=36V, VREF=0; Fig3 | 2 |
| Dynamic Impedance | ZKA |  | 0.15 | 0.5 | Ω | VKA=VREF, IKA=1~100mA, f≤1.0KHz | 2 |
| Cathode Voltage | VKA |  |  | 37 | V | Ta=25℃ | 1 |
| Cathode Current Range (Continuous) | IKA | -100 |  | 150 | mA | Ta=25℃ | 1 |
| Reference Input Current Range | IREF | -0.05 |  | 10 | mA | Ta=25℃ | 1 |
| Maximum Power Dissipation | PD |  |  | 350 | mW | Ta=25℃ | 1 |
| Operating Junction Temperature | TJ |  |  | 150 | °C | Ta=25℃ | 1 |
| Storage Temperature Range | TSTG | -65 |  | 150 | °C | Ta=25℃ | 1 |
| Cathode Voltage (recommended) | VKA |  |  | 36 | V |  | 1 |
| Cathode Current | IKA | 1 |  | 100 | mA |  | 1 |
| Operating Ambient Temperature Range | TOPR | -25 |  | 85 | °C |  | 1 |

## CAD (KiCad official)

- Symbol: `CD431A`
- Footprint: `Package_TO_SOT_SMD:SOT-23`
- 3D model: SOT-23 (KiCad packages3D, STEP)
- 3D model files: `cd431a-etched.step` / `cd431a-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `cd431a.step` / `cd431a.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [DOWO datasheet](docs/cd431a-datasheet.pdf) (4 pp, sha256 `b70c890b15a7ce63`, retrieved 2026-11-04, tier: lcsc)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-haiku-5-5` (text), consensus `claude-sonnet-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/cd431a-datasheet.pdf)