GS8551-TR from Gainsil, in a SOT-23-5. 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	OUT	output	Amplifier output. Rail-to-rail output swings within ~5mV of the supply rails under light loads (>100kΩ) and within ~60mV under 10kΩ loads. Short-circuit limited to ~60mA.
2	VSS	power_in	Negative supply / ground. Connect to GND for single-supply operation (1.8V to 5.5V), or to the negative rail for dual-supply operation (±0.9V to ±2.75V). Bypass with a 0.1µF ceramic capacitor to ground in dual-supply mode.
3	IN+	input	Non-inverting amplifier input. Rail-to-rail common-mode range extends 100mV beyond the supply rails (VSS-0.1V to VDD+0.1V). Input bias current is 20pA typical; absolute input voltage must remain between VSS-0.5V and VDD+0.5V.
4	IN-	input	Inverting amplifier input. Rail-to-rail common-mode range extends 100mV beyond the supply rails. Input bias current is 20pA typical; absolute input voltage must remain between VSS-0.5V and VDD+0.5V.
5	VDD	power_in	Positive supply. 1.8V to 5.5V single-supply, or up to +2.75V in dual-supply operation. Absolute max VDD-to-VSS is 7.5V. Bypass with a 0.1µF ceramic capacitor close to the pin.

Key specifications

Parameter	Value
Manufacturer	Gainsil
Package	SOT-23-5
Category	Op-amp/Cmp
Pins	5

Ordering variants

Same part, different packaging or reel option.

GS8551-TR
GS8551-SR

CAD (KiCad official)

Symbol: GS8551-TR
Footprint: Package_TO_SOT_SMD:SOT-23-5
3D model: SOT-23-5 (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`gs8551-tr.step`	85 KB	You want the bare part, or you mark your own boards.
`gs8551-tr-etched.step`	1.9 MB	You want the part with `GS8551-TR` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 452 faces against 102 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: Gainsil datasheet (14 pp, sha256 dc9b0f2b6cedff03, 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