# MMTL431M

**CBI** · Voltage Reference · SOT-23

MMTL431M from CBI, in a SOT-23. 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 | REF | input | Reference input. Sensing input to the internal error amplifier; regulates so that V(REF) equals the internal 2.495 V bandgap. Typical reference input current 1.5 μA (max 4 μA). |
| 2 | K | passive | Cathode. Shunt-regulator output terminal; sinks 1 to 100 mA in regulation with V(KA) ranging from V(REF) up to 36 V (absolute max 37 V). Off-state leakage typ 0.05 μA at V(KA)=36 V. |
| 3 | A | passive | Anode. Common/return terminal for the shunt regulator; typically tied to circuit ground in the reference-divider configuration. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | CBI |
| Package | SOT-23 |
| Category | PMIC |
| Pins | 3 |

## Ordering variants

Same part, different packaging or reel option.

- `MMTL431MM`

## Electrical characteristics

Limits as printed in the datasheet (page.json `metadata.characteristics` carries them as data).

| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| Cathode Voltage | VKA |  |  | 37 | V |  | 1 |
| Cathode Current Range (Continuous) | IKA | -100 |  | 150 | mA |  | 1 |
| Reference Input Current Range | IREF | -0.05 |  | 10 | mA |  | 1 |
| Power Dissipation | PD |  |  | 350 | mW |  | 1 |
| Operating Temperature Range | Topr | -25 |  | 85 | °C |  | 1 |
| Junction Temperature | Tj |  |  | 150 | °C |  | 1 |
| Storage Temperature Range | Tstg | -65 |  | 150 | °C |  | 1 |
| Cathode Voltage (recommended) | VKA |  |  | 36 | V | Printed minimum is VREF (not a number) | 1 |
| Cathode Current (recommended) | IKA | 1 |  | 100 | mA |  | 1 |
| Reference Input Voltage, 0.5% VREF grade | VREF | 2.483 | 2.495 | 2.507 | V | at VKA = VREF, IKA = 10 mA, Ta = 25°C | 1 |
| Reference Input Voltage, 1% VREF grade | VREF | 2.47 | 2.495 | 2.52 | V | at VKA = VREF, IKA = 10 mA, Ta = 25°C | 1 |
| Reference Input Voltage, 2% VREF grade | VREF | 2.445 | 2.495 | 2.545 | V | at VKA = VREF, IKA = 10 mA, Ta = 25°C | 1 |
| Deviation of Reference Input Voltage Over Temperature | ΔVREF/ΔT |  | 4.5 | 17 | mV | at VKA = VREF, IKA = 10 mA, -25°C ≤ Ta ≤ +85°C | 1 |
| Ratio of Change in Reference Input Voltage to Change in Cathode Voltage | ΔVREF/ΔVKA |  | -1 | -2.7 | mV/V | at IKA = 10 mA, ΔVKA = 10 V to VREF | 1 |
| Ratio of Change in Reference Input Voltage to Change in Cathode Voltage | ΔVREF/ΔVKA |  | -0.5 | -2 | mV/V | at IKA = 10 mA, ΔVKA = 36 V to 10 V | 1 |
| Reference Input Current | IREF |  | 1.5 | 4 | μA | at IKA = 10 mA, R1 = 10 KΩ, R2 = ∞ | 1 |
| Deviation of Reference Input Current Over Full Temperature | ΔIREF/ΔT |  | 0.4 | 1.2 | μA | at IKA = 10 mA, R1 = 10 KΩ, R2 = ∞, -25°C ≤ Ta ≤ +85°C | 1 |
| Minimum Cathode Current for Regulation | IKA(min) |  | 0.45 | 1 | mA | at VKA = VREF | 1 |
| Off-Stage Cathode Current | IKA(OFF) |  | 0.05 | 1 | μA | at VKA = 36 V, VREF = 0 | 1 |
| Dynamic Impedance | ZKA |  | 0.15 | 0.5 | Ω | at VKA = VREF, IKA = 1 to 100 mA, f ≤ 1 KHz | 1 |

## CAD (KiCad official)

- Symbol: `MMTL431M`
- Footprint: `Package_TO_SOT_SMD:SOT-23`
- 3D model: SOT-23 (KiCad packages3D, STEP)
- 3D model files: `mmtl431m-etched.step` / `mmtl431m-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `mmtl431m.step` / `mmtl431m.glb` are the bare package body.

## 3D model downloads

Two STEP files. Same geometry, different body top:

| File | Size | Use it when |
|---|---|---|
| [`mmtl431m.step`](mmtl431m.step) | 59 KB | You want the bare part, or you mark your own boards. |
| [`mmtl431m-etched.step`](mmtl431m-etched.step) | 1.1 MB | You want the part with `MMTL431M` already on it. |

The marking in the etched file is real recessed geometry cut into the solid, not a
texture or a decal: 294 faces against 69 in the bare model. It
survives export, section views, and rendering in any CAD tool, and it drops straight
into KiCad or Fusion with no extra setup.

## Provenance

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

- **Datasheet:** [CBI datasheet](docs/mmtl431m-datasheet.pdf) (3 pp, sha256 `1daadd9e4fa3c494`, retrieved 2026-08-17, tier: lcsc)
- **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/mmtl431m-datasheet.pdf)