L78L18CD13TR from STMicroelectronics, in a SO-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 +18 V output. Delivers up to 100 mA with typical dropout of ~2 V. Bypass with 0.1 µF to GND close to the pin.
2	GND	power_in	Ground / common return. Pins 2, 3, 6 and 7 are electrically commoned to the die-attach flag internally to reduce package thermal resistance; all four should be tied to the ground plane for best heat-sinking.
3	GND	power_in	Ground / common return. Internally tied to the die-attach flag together with pins 2, 6 and 7 for improved thermal dissipation.
4	NC	unconnected	No internal connection. May be left floating or tied to GND for improved layout.
5	NC	unconnected	No internal connection. May be left floating or tied to GND for improved layout.
6	GND	power_in	Ground / common return. Internally tied to the die-attach flag together with pins 2, 3 and 7 for improved thermal dissipation.
7	GND	power_in	Ground / common return. Internally tied to the die-attach flag together with pins 2, 3 and 6 for improved thermal dissipation.
8	VIN	power_in	Unregulated DC input. For the 18 V variant the absolute maximum input voltage is 35 V (VO = 12 to 15 V range) / 40 V (VO = 18 to 24 V range); nominal operating input is roughly VOUT + 2 V dropout upward. Bypass with 0.33 µF to GND close to the pin.

Key specifications

Parameter	Value
Manufacturer	STMicroelectronics
Package	SO-8
Category	PMIC
Pins	8

Ordering variants

Same part, different packaging or reel option.

L78L18CD13TR
L78L18CD13TRZ
L78L18CD13TRAZ
L78L18CD13TRACZ

CAD (KiCad official)

Symbol: L78L18CD13TR
Footprint: Package_SO:TI_SO-PowerPAD-8
3D model: SO-8 (KiCad packages3D, STEP)

Provenance

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

Datasheet: STMicroelectronics datasheet (40 pp, sha256 8b73c521b7f1b36e, 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