# L78M09CDT-TR

**STMicroelectronics** · Voltage Regulators - Linear, Low Drop Out (LDO) Regulators · TO-252-2(DPAK)

L78M09CDT-TR from STMicroelectronics, in a TO-252-2(DPAK). 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 | INPUT | power_in | Unregulated positive DC input. For a 9 V output, V_I must be at least a few volts above V_O; absolute maximum V_I = 35 V (for V_O = 5-18 V). A 0.33 uF ceramic capacitor to GND is recommended close to the pin. |
| 2 | GROUND | power_in | Common ground reference. On DPAK, pin 2 is electrically tied to the exposed heat-sink tab, which is the primary thermal path (R_thJC = 8 C/W, R_thJA = 100 C/W). Solder the tab to a copper pour for heat dissipation. |
| 3 | OUTPUT | power_out | Regulated +9 V DC output, up to 0.5 A (peak >0.5 A with adequate heatsinking). Internally current-limited and SOA-protected. A 0.1 uF ceramic capacitor to GND is recommended to improve transient response and stability. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | STMicroelectronics |
| Package | TO-252-2(DPAK) |
| Category | PMIC |
| Pins | 3 |

## Ordering variants

Same part, different packaging or reel option.

- `L78M09CDT-TRT`
- `L78M09CDT-TRP`
- `L78M09CDT-TR`

## 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 | VO | 8.65 | 9 | 9.35 | V |  | 13 |
| Output voltage | VO | 8.55 | 9 | 9.45 | V | IO = 5 to 350 mA, VI = 11.5 to 24 V | 13 |
| Line regulation | ∆VO |  |  | 100 | mV | VI = 11.5 to 25 V, IO = 200 mA | 13 |
| Line regulation | ∆VO |  |  | 50 | mV | VI = 12 to 25 V, IO = 200 mA | 13 |
| Load regulation | ∆VO |  |  | 180 | mV | IO = 5 to 500 mA, TJ = 25 °C | 13 |
| Load regulation | ∆VO |  |  | 90 | mV | IO = 5 to 200 mA, TJ = 25 °C | 13 |
| Quiescent current | Id |  |  | 6 | mA |  | 13 |
| Quiescent current change | ∆Id |  |  | 0.5 | mA | IO = 5 to 350 mA | 13 |
| Quiescent current change | ∆Id |  |  | 0.8 | mA | IO = 200 mA, VI = 11.5 to 25 V | 13 |
| Output voltage drift | ∆VO/∆T |  |  | -0.5 | mV/°C | IO = 5 mA, TJ = 0 to 125 °C | 13 |
| Supply voltage rejection | SVR |  |  | 56 | dB | VI = 12.5 to 23 V, f = 120 Hz, IO = 300 mA | 13 |
| Output noise voltage | eN |  |  | 58 | µV | B = 10 Hz to 100 kHz | 13 |
| Dropout voltage | Vd |  |  | 2 | V |  | 13 |
| Short circuit current | Isc |  |  | 250 | mA | VI = 35 V | 13 |
| DC input voltage (for VO = 5 to 18 V) | VI |  |  | 35 | V | for VO = 5 to 18 V | 5 |
| Storage temperature range | TSTG | -65 |  | 150 | °C |  | 5 |
| Operating junction temperature range | TOP | 0 |  | 150 | °C | for L78MxxC | 5 |
| Thermal resistance junction-case (DPAK) | RthJC |  |  | 8 | °C/W | DPAK | 5 |
| Thermal resistance junction-ambient (DPAK) | RthJA |  |  | 100 | °C/W | DPAK | 5 |

## CAD (KiCad official)

- Symbol: `L78M09CDT-TR`
- Footprint: `Package_TO_SOT_SMD:TO-252-2`
- 3D model: TO-252-2(DPAK) (KiCad packages3D, STEP)
- 3D model files: `l78m09cdt-tr-etched.step` / `l78m09cdt-tr-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `l78m09cdt-tr.step` / `l78m09cdt-tr.glb` are the bare package body.

## 3D model downloads

Two STEP files. Same geometry, different body top:

| File | Size | Use it when |
|---|---|---|
| [`l78m09cdt-tr.step`](l78m09cdt-tr.step) | 119 KB | You want the bare part, or you mark your own boards. |
| [`l78m09cdt-tr-etched.step`](l78m09cdt-tr-etched.step) | 1.7 MB | You want the part with `L78M09CDT-TR` already on it. |

The marking in the etched file is real recessed geometry cut into the solid, not a
texture or a decal: 458 faces against 83 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/l78m09cdt-tr.pdf) (47 pp, sha256 `7cee4c5f6a43332c`, 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/l78m09cdt-tr-datasheet.pdf)