# L78L15ABUTR

**STMicroelectronics** · Voltage Regulators - Linear, Low Drop Out (LDO) Regulators · SOT-89-3

L78L15ABUTR from STMicroelectronics, in a SOT-89-3. 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 +15 V positive output. Delivers up to 100 mA with typical dropout of ~1.7 V (VIN must be ≥ ~17 V for full regulation). A 0.1 µF ceramic bypass capacitor to GND close to this pin is recommended to improve transient response and stability. |
| 2 | GND | power_in | Device ground / common return for input and output. In the SOT-89 package the GND pin is electrically bonded to the die-attach flag on the bottom of the package, which serves as the primary thermal path to the PCB copper. |
| 3 | VIN | power_in | Unregulated positive DC input. Absolute maximum 35 V for the 15 V variant; recommended VIN ≥ VOUT + dropout (~17 V) for full regulation. Bypass with a 0.33 µF ceramic capacitor to GND close to this pin to prevent oscillation and improve line transient response. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | STMicroelectronics |
| Package | SOT-89-3 |
| Category | PMIC |
| Pins | 3 |

## Ordering variants

Same part, different packaging or reel option.

- `L78L15ABUTR`
- `L78L15ABUTRZ`
- `L78L15ABUTRAZ`
- `L78L15ABUTRABZ`
- `L78L15ABUTRCZ`
- `L78L15ABUTRACZ`
- `L78L15ABUTRD`
- `L78L15ABUTRD-TR`
- `L78L15ABUTRABD`

## Electrical characteristics

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

| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| Output voltage (TJ = 25 °C) | VO | 14.4 | 15 | 15.6 | V | TJ = 25 °C | 22 |
| Output voltage (IO = 1 to 40 mA) | VO | 14.25 |  | 15.75 | V | IO = 1 to 40 mA, VI = 17.5 to 30 V | 22 |
| Output voltage (IO = 1 to 70 mA) | VO | 14.25 |  | 15.75 | V | IO = 1 to 70 mA, VI = 23 V | 22 |
| Line regulation | ∆VO |  |  | 300 | mV | VI = 17.5 to 30 V, TJ = 25 °C | 22 |
| Line regulation | ∆VO |  |  | 250 | mV | VI = 20 to 30 V, TJ = 25 °C | 22 |
| Load regulation | ∆VO |  |  | 150 | mV | IO = 1 to 100 mA, TJ = 25 °C | 22 |
| Load regulation | ∆VO |  |  | 75 | mV | IO = 1 to 40 mA, TJ = 25 °C | 22 |
| Quiescent current | Id |  |  | 6.5 | mA | TJ = 25 °C | 22 |
| Quiescent current | Id |  |  | 6 | mA | TJ = 125 °C | 22 |
| Quiescent current change | ∆Id |  |  | 0.1 | mA | IO = 1 to 40 mA | 22 |
| Quiescent current change | ∆Id |  |  | 1.5 | mA | VI = 20 to 30 V | 22 |
| Supply voltage rejection | SVR | 34 | 39 |  | dB | VI = 18.5 to 28.5 V, f = 120 Hz, IO = 40 mA, TJ = 25 °C | 22 |
| Dropout voltage | Vd |  |  | 1.7 | V |  | 22 |
| Output noise voltage | eN |  | 90 |  | µV | B = 10 Hz to 100 kHz, TJ = 25 °C | 22 |
| DC input voltage | VI |  |  | 35 | V | VO = 12 to 15 V | 5 |
| Output current | IO |  |  | 100 | mA |  | 5 |
| Storage temperature range | TSTG | -65 |  | 150 | °C |  | 5 |
| Operating junction temperature range (AB grade) | TOP | -40 |  | 125 | °C | for L78LxxAB | 5 |
| Thermal resistance junction-ambient (SOT-89) | RthJA |  |  | 55 | °C/W | Considering 6 cm² of copper Board heat-sink (note 1) | 5 |

## CAD (KiCad official)

- Symbol: `L78L15ABUTR`
- Footprint: `Package_TO_SOT_SMD:SOT-89-3`
- 3D model: SOT-89-3 (KiCad packages3D, STEP)
- 3D model files: `l78l15abutr-etched.step` / `l78l15abutr-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `l78l15abutr.step` / `l78l15abutr.glb` are the bare package body.

## 3D model downloads

Two STEP files. Same geometry, different body top:

| File | Size | Use it when |
|---|---|---|
| [`l78l15abutr.step`](l78l15abutr.step) | 57 KB | You want the bare part, or you mark your own boards. |
| [`l78l15abutr-etched.step`](l78l15abutr-etched.step) | 1.4 MB | You want the part with `L78L15ABUTR` already on it. |

The marking in the etched file is real recessed geometry cut into the solid, not a
texture or a decal: 378 faces against 42 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:** [STMicroelectronics datasheet](https://www.st.com/resource/en/datasheet/l78l15abutr.pdf) (45 pp, sha256 `43922ae159face7e`, retrieved 2026-08-17, tier: manufacturer)
- **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/l78l15abutr-datasheet.pdf)