# LM321H-TR

**Gainsil** · Operational Amplifier · SOT-23-5

LM321H-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 | IN+ | input | Non-inverting analog input of the op-amp. Common-mode input range includes ground and extends to VDD-1.5V. Typical input bias current 20nA. |
| 2 | VSS | power_in | Negative supply / ground. Connect to GND in single-supply operation (3V to 36V VDD) or to the negative rail (down to -18V) in dual-supply operation. Bypass with a 0.1µF ceramic capacitor to ground in split-supply designs. |
| 3 | IN- | input | Inverting analog input of the op-amp. Same common-mode range and bias current characteristics as IN+. |
| 4 | OUT | output | Op-amp output. Swings from 0V to VCC-1.5V; sources/sinks 40mA typical (60mA max) into a 10Ω load to VS/2. Output high VOH ≥12V and low VOL ≤5mV typical at RL=10kΩ with VS=15V. |
| 5 | VDD | power_in | Positive supply. Single-supply range 3V to 36V, or up to +18V in dual-supply operation. Bypass with a 0.1µF ceramic capacitor to VSS placed 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.

- `LM321H-TR`
- `LM321H-TRLM358H-SR`
- `LM321H-TRLM358H-MR`
- `LM324H-SR`
- `LM324H-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 |
|---|---|---|---|---|---|---|---|
| Common-Mode Rejection Ratio | CMRR | 60 | 70 |  | dB | VCM = 0V to Vs-1.5V | 3 |
| Open-Loop Voltage Gain | AOL | 85 | 100 |  | dB | RL = 5kΩ, VO = 1V to 11V | 3 |
| Input Offset Voltage | VOS |  | 0.4 | 5 | mV | VCM = VS/2 | 3 |
| Output Voltage Swing from Rail (VOH) | VOH | 11 |  |  | V | RL = 2kΩ | 3 |
| Output Voltage Swing from Rail (VOL) | VOL |  | 5 | 20 | mV | RL = 2kΩ | 3 |
| Output Voltage Swing from Rail (VOH) | VOH | 13 | 12 |  | V | RL = 10kΩ | 3 |
| Output Current (source) | ISOURCE |  | 40 | 60 | mA | RL = 10Ω to VS/2 | 3 |
| Output Current (sink) | ISINK |  | 40 | 60 | mA | RL = 10Ω to VS/2 | 3 |
| Operating Voltage Range (minimum) |  | 3 |  |  | V |  | 3 |
| Operating Voltage Range (maximum) |  |  |  | 36 | V |  | 3 |
| Power Supply Rejection Ratio | PSRR | 70 | 100 |  | dB | VS = +5V to +36V, VCM = +0.5V | 3 |
| Quiescent Current / Amplifier | IQ |  | 0.25 | 2 | mA | VS = 36V, RL=∞ | 3 |
| Power Supply Voltage | Vcc |  |  | 40 | V | Printed as ±20V or 40V | 2 |
| Differential input voltage | VI(DIFF) |  |  | 40 | V |  | 2 |
| Input Voltage | VI | -0.3 |  | 40 | V |  | 2 |
| Operating Temperature Range | Topr | -40 |  | 125 | °C |  | 2 |
| Storage Temperature Range | Tstg | -65 |  | 150 | °C |  | 2 |
| Input Bias Current | IB |  | 20 |  | nA |  | 3 |
| Input Offset Current | IOS |  | 5 |  | nA |  | 3 |
| Input Offset Voltage Drift | ΔVOS/ΔT |  | 7 |  | μV/℃ |  | 3 |
| Gain-Bandwidth Product | GBP |  | 1 |  | MHz |  | 3 |
| Slew Rate | SR |  | 0.2 |  | V/μs | G = +1, 2V Output Step | 3 |

## CAD (KiCad official)

- Symbol: `LM321H-TR`
- Footprint: `Package_TO_SOT_SMD:SOT-23-5`
- 3D model: SOT-23-5 (KiCad packages3D, STEP)
- 3D model files: `lm321h-tr-etched.step` / `lm321h-tr-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `lm321h-tr.step` / `lm321h-tr.glb` are the bare package body.

## 3D model downloads

Two STEP files. Same geometry, different body top:

| File | Size | Use it when |
|---|---|---|
| [`lm321h-tr.step`](lm321h-tr.step) | 85 KB | You want the bare part, or you mark your own boards. |
| [`lm321h-tr-etched.step`](lm321h-tr-etched.step) | 1.4 MB | You want the part with `LM321H-TR` already on it. |

The marking in the etched file is real recessed geometry cut into the solid, not a
texture or a decal: 360 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](docs/lm321h-tr-datasheet.pdf) (14 pp, sha256 `1b038a6ed7d0cd56`, 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/lm321h-tr-datasheet.pdf)