# OPA551UA

**Texas Instruments** · Operational Amplifier · SOIC-8

OPA551UA from Texas Instruments, in a SOIC-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 | V- | power_in | Negative (lowest) power supply. Operating supply range ±4 V to ±30 V (8 V to 60 V between rails). Pins 1, 4, and 5 are internally connected for improved thermal performance; pin 4 must carry the primary V- supply current, pins 1 and 5 should be connected to a thermal mass rather than used as feedthroughs to V-. |
| 2 | -IN | input | Inverting op-amp input. Common-mode range (V-)+2.5 V to (V+)-2.5 V; input bias current ±20 pA typ (±100 pA max). Internal clamp diodes protect against voltages beyond the rails; external input current must be limited to 5 mA. |
| 3 | +IN | input | Noninverting op-amp input. Common-mode range (V-)+2.5 V to (V+)-2.5 V; input bias current ±20 pA typ. Internal clamp diodes protect against voltages beyond the rails; external input current must be limited to 5 mA. |
| 4 | V- | power_in | Negative (lowest) power supply - primary current carrier for V-. Operating supply range ±4 V to ±30 V (8 V to 60 V total between rails). Bypass with 0.1 µF (and 10 µF) capacitor near the pin. |
| 5 | V- | power_in | Negative (lowest) power supply. Internally tied to pins 1 and 4 for improved thermal performance. Should be connected to a thermal mass rather than used as a PCB feedthrough for V-. |
| 6 | Out | output | Amplifier output. Swings to within ~2 V of the rails at 10 mA and ~3 V of the rails at 200 mA. Continuous output current up to ±200 mA; short-circuit current limited to approximately ±380 mA. Stable driving capacitive loads (see Figure 19 for allowed CL vs. gain). |
| 7 | V+ | power_in | Positive (highest) power supply. Operating supply range ±4 V to ±30 V (8 V to 60 V total between rails). Quiescent current ±7 mA typ (±8.5 mA max). Bypass with 0.1 µF (and 10 µF) capacitor near the pin. |
| 8 | Flag | output | Thermal-shutdown indicator (current-source output). Sources ~50 nA (1 µA max) during normal operation and 80-160 µA (120 µA typ) when the die exceeds ~160 °C and enters thermal shutdown (resets at ~140 °C). Compliance range V- to (V+)-1.5 V; an external pull-down resistor converts the current to a logic-level signal. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Texas Instruments |
| Package | SOIC-8 |
| Category | Op-amp/Cmp |
| Pins | 8 |

## Ordering variants

- `OPA551UA`
- `OPA551UA/2K5`
- `OPA551UAE4`
- `OPA551UAPAG4`
- `OPA551UAFA/500`
- `OPA551UAFA/500G3`
- `OPA551UAFAKTWT`
- `OPA551UAFAKTWTG3`

## Electrical characteristics

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

| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| Input offset voltage | VOS | -3 | 1 | 3 | mV | VCM = 0 V, IO = 0 mA | 5 |
| Input offset voltage over temperature | VOS | -5 |  | 5 | mV | TJ = –40°C to 125°C | 5 |
| Input offset voltage vs power supply (PSRR) | PSRR |  | 10 | 30 | µV/V | VS = ±4 V to ±30 V, VCM = 0 V | 5 |
| Input bias current | IB | -100 | 20 | 100 | pA |  | 5 |
| Input offset current | IOS | -100 | 3 | 100 | pA |  | 5 |
| Common-mode rejection ratio | CMRR | 92 | 102 |  | dB | –27.5 V < VCM < +27.5 V | 5 |
| Open-loop voltage gain | AOL | 110 | 126 |  | dB | RL = 3 kΩ, –28 V < VO < +28 V | 5 |
| Open-loop voltage gain over temperature | AOL | 100 |  |  | dB | RL = 3 kΩ, –28 V < VO < +28 V, TJ = –40°C to 125°C | 5 |
| Maximum continuous output current | IO | -200 |  | 200 | mA | DC | 6 |
| Thermal shutdown status output, normal operation (sourcing) |  |  | 0.05 | 1 | µA | Normal operation, sourcing | 6 |
| Thermal shutdown status output, thermal shutdown (sourcing) |  | 80 | 120 | 160 | µA | Thermal shutdown, sourcing | 6 |
| Operating voltage range (per supply, ±) |  | 4 |  | 30 | V |  | 6 |
| Quiescent current | IQ |  | 7 | 8.5 | mA | IO = 0 mA | 6 |
| Quiescent current over temperature | IQ |  |  | 10 | mA | TJ = –40°C to 125°C | 6 |
| Specified temperature range (electrical) | TJ | -40 |  | 125 | °C |  | 6 |
| Operating temperature range (electrical) | TJ | -55 |  | 125 | °C |  | 6 |
| Supply voltage VS (recommended) | VS | 8 |  | 60 | V |  | 4 |
| Specified temperature (recommended) |  | -40 |  | 125 | °C |  | 4 |
| Supply voltage VS = (V+) to (V–) | VS |  |  | 60 | V |  | 4 |
| Operating temperature | TA | -55 |  | 125 | °C |  | 4 |
| Junction temperature | TJ |  |  | 150 | °C |  | 4 |
| Storage temperature | Tstg | -65 |  | 150 | °C |  | 4 |
| Electrostatic discharge, human-body model (HBM) | V(ESD) | -3000 |  | 3000 | V | ANSI/ESDA/JEDEC JS-001 | 4 |
| Junction-to-ambient thermal resistance | RθJA |  | 96.7 |  | °C/W | SOIC (D) 8-pin package | 4 |
| Junction-to-case (top) thermal resistance | RθJC(top) |  | 38.7 |  | °C/W | SOIC (D) 8-pin package | 4 |
| Junction-to-board thermal resistance | RθJB |  | 38.2 |  | °C/W | SOIC (D) 8-pin package | 4 |

## CAD (KiCad official)

- Symbol: `OPA551UA`
- Footprint: `Package_SO:SOIC-8_3.9x4.9mm_P1.27mm`
- 3D model: SOIC-8 (KiCad packages3D, STEP)
- 3D model files: `opa551ua-etched.step` / `opa551ua-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `opa551ua.step` / `opa551ua.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Texas Instruments datasheet](https://www.ti.com/lit/ds/symlink/opa551ua.pdf) (None pp, sha256 `bc4b2856546ba466`, 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/opa551ua-datasheet.pdf)