# LM2931AD50R

**STMicroelectronics** · Voltage Regulators - Linear, Low Drop Out (LDO) Regulators · SOIC-8

LM2931AD50R from STMicroelectronics, 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 | VOUT | power_out | Regulated 5.0 V output. Typical 5.0 V (min 4.75 V, max 5.25 V) at IO = 100 mA over the full VI = 6 to 26 V and TJ = -40 to 125 °C range. Requires a ≥100 µF output capacitor for stability. |
| 2 | GND | power_in | Device ground / reference return. |
| 3 | GND | power_in | Device ground / reference return (tied internally to the other GND pins; multiple GND pins aid heat sinking on SO-8). |
| 4 | NC | unconnected | Not connected on the fixed-output version (LM2931AD50R). This pin serves as the ADJ feedback input only on the adjustable (LM2931D-R) variant; leave floating on this part. |
| 5 | INHIBIT | input | Active-high shutdown / inhibit logic input. Regulator is enabled when VINH < 1.2 V (VIL) and disabled when VINH > 3.25 V (VIH). Inhibit input current IINH ≈ 22 µA typ (50 µA max) at VINH = 2.5 V. Absolute maximum inhibit input voltage is 40 V. |
| 6 | GND | power_in | Device ground / reference return (tied internally to the other GND pins). |
| 7 | GND | power_in | Device ground / reference return (tied internally to the other GND pins). |
| 8 | VIN | power_in | Unregulated supply input. Recommended operating range 6 V to 26 V (max operating 26 V min); tolerates transient input up to 60 V (T < 100 ms) and reverse polarity down to -15 V DC / -50 V transient. Decouple with a 0.1 µF input capacitor. Absolute maximum DC input voltage 40 V. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | STMicroelectronics |
| Package | SOIC-8 |
| Category | Power Management (PMIC) |
| Pins | 8 |

## Ordering variants

Same part, different packaging or reel option.

- `LM2931AD50R`
- `LM2931AD33R`
- `LM2931D-R`
- `LM2931ADT50R`
- `LM2931ADT50RY`
- `LM2931ADT33RY`
- `LM2931AZ50R`

## Electrical characteristics

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

| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| Maximum operating input voltage | VI |  |  | 26 | V | IO = 10 mA, TJ = -40 to 125 °C | 7 |
| Output voltage | VO | 4.81 | 5 | 5.19 | V |  | 7 |
| Output voltage | VO | 4.75 | 5 | 5.25 | V | IO = 100 mA, VI = 6 to 26 V, TJ = -40 to 125°C | 7 |
| Line regulation | DVO |  | 2 | 10 | mV | VI = 9 to 16 V | 7 |
| Line regulation | DVO |  | 4 | 30 | mV | VI = 6 to 26 V | 7 |
| Load regulation | DVO |  | 15 | 50 | mV | IO = 5 to 100 mA | 7 |
| Dropout voltage | Vd |  | 90 | 200 | mV | IO = 10 mA | 7 |
| Dropout voltage | Vd |  | 250 | 600 | mV | IO = 100 mA | 7 |
| Quiescent current ON MODE | Id |  | 2.5 | 30 | mA | ON MODE IO = 100 mA | 7 |
| Quiescent current OFF MODE | Id |  | 0.3 | 1 | mA | OFF MODE VINH = 2.5 V, RLOAD = 500 Ω | 7 |
| Short circuit current | ISC |  | 100 | 300 | mA |  | 7 |
| Supply voltage rejection | SVR | 55 | 75 |  | dB | IO = 100 mA, VI = 14 ± 2 V, f = 120 Hz | 7 |
| Control input voltage low | VIL |  |  | 1.2 | V | TJ = -40 to 125 °C | 7 |
| Control input voltage high | VIH | 2 |  | 3.25 | V | TJ = -40 to 125 °C | 7 |
| Inhibit input current | IINH |  | 22 | 50 | µA | VINH = 2.5 V | 7 |
| Transient input voltage | VI |  | 60 | 70 | V | RLOAD = 500 Ω, Ƭ < 100 ms | 7 |
| Reverse polarity input voltage | VI | -50 |  | -15 | V | VO = ± 0.3 V, RLOAD = 500 Ω | 7 |
| Reverse polarity input voltage transient | VI | -50 |  |  | V | RLOAD = 500 Ω, Ƭ < 100 ms | 7 |
| Output noise voltage | eN |  |  | 500 | µVRMS | B = 10 Hz to 100 kHz | 7 |
| DC positive input voltage | VI |  |  | 40 | V |  | 4 |
| DC reverse input voltage | VI | -15 |  |  | V |  | 4 |
| Transient input voltage | VI |  |  | 60 | V | Ƭ < 100 ms | 4 |
| Transient reverse input voltage | VI | -50 |  |  | V | Ƭ < 100 ms | 4 |
| Inhibit input voltage | VINH |  |  | 40 | V |  | 4 |
| Storage temperature range | TSTG | -65 |  | 150 | °C |  | 4 |
| Operating junction temperature range | TOP | -40 |  | 125 | °C |  | 4 |
| Thermal resistance junction-case (SO-8) | RthJC |  | 20 |  | °C/W |  | 4 |
| Thermal resistance junction-ambient (SO-8) | RthJA |  | 55 |  | °C/W | Note (1): considering 6 cm2 of copper board heat-sink | 4 |

## CAD (KiCad official)

- Symbol: `LM2931AD50R`
- Footprint: `Package_SO:SOIC-8_3.9x4.9mm_P1.27mm`
- 3D model: SOIC-8 (KiCad packages3D, STEP)
- 3D model files: `lm2931ad50r-etched.step` / `lm2931ad50r-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `lm2931ad50r.step` / `lm2931ad50r.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [STMicroelectronics datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8588879859115941888) (24 pp, sha256 `07bd8d19d77c6060`, 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/lm2931ad50r-datasheet.pdf)