# RS8491XK

**Jiangsu RUNIC Tech** · Operational Amplifier · SOIC-8

RS8491XK from Jiangsu RUNIC Tech, in a SOIC-8. Pinout and pin descriptions extracted from the manufacturer datasheet (extract_pins, cross-checked by a second model); symbol, footprint, and 3D from KiCad-official CAD.

## Pinout

| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | +IN | input | Noninverting input of the amplifier, which also drives the internal guard buffer input. |
| 2 | GRD | passive | Guard pin that is part of the integrated guard buffer and is used to route the guard ring around the sensitive inputs. |
| 3 | IC | passive | Internal connection that must be connected to V- or left unconnected. |
| 4 | V- | power_in | Negative supply voltage. |
| 5 | V+ | power_in | Positive supply voltage. |
| 6 | OUT | output | Amplifier output, which has a rail-to-rail output stage. |
| 7 | GRD | passive | Guard pin that is part of the integrated guard buffer and is used to route the guard ring around the sensitive inputs. |
| 8 | -IN | input | Inverting input of the amplifier. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Jiangsu RUNIC Tech |
| Package | SOIC-8 |
| Category | Operational Amplifier/Comparator |
| Pins | 8 |

## 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 Bias Current | IB | -200 | 50 | 200 | fA | 25°C, VS=5V | 7 |
| Input Offset Current | IOS | -200 | 50 | 200 | fA | 25°C, VS=5V | 7 |
| Input Offset Voltage | VOS | -400 | 54 | 400 | μV | VCM=VS/2, 25°C, VS=5V | 7 |
| Input Offset Voltage | VOS | -1000 |  | 1000 | μV | VCM=1.5V to 3V, -40°C to 85°C, VS=5V | 7 |
| Input Offset Voltage | VOS | -600 |  | 600 | μV | VCM=0V to 3V, 25°C, VS=5V | 7 |
| Input Offset Voltage Average Drift | VOS TC | -5 |  | 5 | μV/°C | VCM=1.5V to 3V, -40°C to 85°C, VS=5V | 7 |
| Power-Supply Rejection Ratio | PSRR | 83 | 106 |  | dB | VS=5V to 25V, 25°C | 7 |
| Power-Supply Rejection Ratio | PSRR | 70 |  |  | dB | VS=5V to 25V, -40°C to 125°C | 7 |
| Common-Mode Voltage Range | VCM | 0 |  | 3 | V | VS=5V, -40°C to 125°C | 7 |
| Common-Mode Rejection Ratio | CMRR | 83 | 102 |  | dB | VCM=1.5V to 3.0V, 25°C, VS=5V | 7 |
| Common-Mode Rejection Ratio | CMRR | 70 |  |  | dB | VCM=1.5V to 3.0V, -40°C to 125°C, VS=5V | 7 |
| Open-Loop Voltage Gain | AOL | 110 | 130 |  | dB | RL=10kΩ to VCM, VOUT=0.2V to 4.3V, 25°C, VS=5V | 7 |
| Open-Loop Voltage Gain | AOL | 105 |  |  | dB | RL=10kΩ to VCM, VOUT=0.2V to 4.3V, -40°C to 125°C, VS=5V | 7 |
| Input Resistance | RIN | 20 |  |  | TΩ |  | 7 |
| Output Voltage High | VOH | 4.92 |  |  | V | RL=2kΩ, 25°C, VS=5V | 8 |
| Output Voltage High | VOH | 4.85 |  |  | V | RL=2kΩ, -40°C to 125°C, VS=5V | 8 |
| Output Voltage High | VOH | 4.98 |  |  | V | RL=10kΩ, 25°C, VS=5V | 8 |
| Output Voltage High | VOH | 4.95 |  |  | V | RL=10kΩ, -40°C to 125°C, VS=5V | 8 |
| Output Voltage Low | VOL |  |  | 133 | mV | RL=2kΩ, 25°C, VS=5V | 8 |
| Output Voltage Low | VOL |  |  | 160 | mV | RL=2kΩ, -40°C to 125°C, VS=5V | 8 |
| Output Voltage Low | VOL |  |  | 29 | mV | RL=10kΩ, 25°C, VS=5V | 8 |
| Output Voltage Low | VOL |  |  | 40 | mV | RL=10kΩ, -40°C to 125°C, VS=5V | 8 |
| Output Source Current | ISOURCE | 30 |  |  | mA | 25°C, VS=5V | 8 |
| Output Sink Current | ISINK | -20 |  |  | mA | 25°C, VS=5V | 8 |
| Quiescent Current Per Amplifier | IQ |  | 1 | 1.6 | mA | IOUT=0A, 25°C, VS=5V | 8 |
| Quiescent Current Per Amplifier | IQ |  |  | 1.8 | mA | IOUT=0A, -40°C to 125°C, VS=5V | 8 |
| Guard Offset Voltage | VGOS | -400 | 75 | 400 | μV | VCM=1.5V to 3V, 25°C, VS=5V | 8 |
| Guard Offset Voltage | VGOS | -800 |  | 800 | μV | VCM=1.5V to 3V, -40°C to 125°C, VS=5V | 8 |
| Guard Offset Voltage | VGOS | -500 |  | 500 | μV | VCM=0.1V to 3V, 25°C, VS=5V | 8 |
| Output Voltage Range |  | 0.1 |  | 3 | V | VGOS<±500μV, 25°C, VS=5V | 8 |
| Supply voltage | VS | 5 |  | 25 | V | Single-supply | 6 |
| Supply voltage | VS | 2.5 |  | 12.5 | V | Dual-supply, printed as ±2.5 to ±12.5 | 6 |
| Supply voltage | VS | -0.7 |  | 28 | V | VS=(V+)-(V-) | 6 |
| Signal input pin current |  | -10 |  | 10 | mA | Signal input pin | 6 |
| Signal output pin current |  | -10 |  | 10 | mA | Signal output pin | 6 |
| Operating temperature range | TA | -40 |  | 125 | °C | Free-air | 6 |
| Junction temperature | TJ | -40 |  | 150 | °C |  | 6 |
| Storage temperature | Tstg | -65 |  | 150 | °C |  | 6 |
| Package thermal impedance | θJA |  |  | 110 | °C/W | SOIC-8(SOP8) | 6 |
| Input Offset Voltage | VOS | -900 | 100 | 900 | μV | VCM=VS/2, 25°C, VS=25V | 9 |
| Input Offset Voltage | VOS | -2000 |  | 2000 | μV | VCM=1.5V to 21V, -40°C to 85°C, VS=25V | 9 |
| Input Offset Voltage Average Drift | VOS TC | -3.5 |  | 3.5 | μV/°C | VCM=1.5V to 23V, -40°C to 85°C, VS=25V | 9 |
| Common-Mode Voltage Range | VCM | 0 |  | 23 | V | VS=25V, -40°C to 125°C | 9 |
| Common-Mode Rejection Ratio | CMRR | 95 | 120 |  | dB | VCM=1.5V to 21V, 25°C, VS=25V | 9 |
| Common-Mode Rejection Ratio | CMRR | 90 |  |  | dB | VCM=1.5V to 21V, -40°C to 125°C, VS=25V | 9 |
| Common-Mode Rejection Ratio | CMRR | 80 | 85 |  | dB | VCM=0 to 23V, 25°C, VS=25V | 9 |
| Open-Loop Voltage Gain | AOL | 110 | 130 |  | dB | RL=10kΩ, VOUT=0.5V to 24.5V, 25°C, VS=25V | 9 |
| Open-Loop Voltage Gain | AOL | 105 |  |  | dB | RL=10kΩ, VOUT=0.5V to 24.5V, -40°C to 125°C, VS=25V | 9 |
| Output Voltage High | VOH | 24.62 |  |  | V | RL=2kΩ, 25°C, VS=25V | 10 |
| Output Voltage High | VOH | 24.5 |  |  | V | RL=2kΩ, -40°C to 125°C, VS=25V | 10 |
| Output Voltage Low | VOL |  |  | 0.61 | V | RL=2kΩ, 25°C, VS=25V | 10 |
| Output Voltage Low | VOL |  |  | 0.75 | V | RL=2kΩ, -40°C to 125°C, VS=25V | 10 |
| Output Voltage Low | VOL |  | 0.13 | 0.2 | V | RL=10kΩ, 25°C, VS=25V | 10 |
| Output Voltage Low | VOL |  |  | 0.22 | V | RL=10kΩ, -40°C to 125°C, VS=25V | 10 |
| Output Source Current | ISOURCE | 70 |  |  | mA | 25°C, VS=25V | 10 |
| Output Sink Current | ISINK | -50 |  |  | mA | 25°C, VS=25V | 10 |
| Guard Offset Voltage | VGOS | -400 | 80 | 400 | μV | VCM=1.5V to 23V, 25°C, VS=25V | 10 |
| Guard Offset Voltage | VGOS | -1000 |  | 1000 | μV | VCM=1.5V to 23V, -40°C to 125°C, VS=25V | 10 |
| Output Voltage Range |  | 0.1 |  | 23.5 | V | VGOS<±500μV, 25°C, VS=25V | 10 |

## CAD (KiCad official)

- Symbol: `RS8491XK`
- Footprint: `Package_SO:SOIC-8_3.9x4.9mm_P1.27mm`
- 3D model: SOIC-8 (KiCad packages3D, STEP)
- 3D model files: `rs8491xk-etched.step` / `rs8491xk-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `rs8491xk.step` / `rs8491xk.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Jiangsu RUNIC Tech datasheet](docs/rs8491xk-datasheet.pdf) (19 pp, sha256 `25ff542b30d2bfbe`, retrieved 2026-10-28, tier: lcsc)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-haiku-5-5` (text), consensus `claude-sonnet-5-5` (agreed), guards: pin_guards 0.1: passed. Pins are checked against the footprint pad set and their cited datasheet pages before publish.
- **CAD:** KiCad official libraries (CC-BY-SA 4.0).

[Datasheet PDF](docs/rs8491xk-datasheet.pdf)