# COS128UA

**COSINE** · Instrumentation OpAmps · SOP-8

COS128UA from COSINE, in a SOP-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 | RG | passive | Gain setting pin. Connect an external gain resistor RG between pin 1 and pin 8 to set voltage gain G = 1 + 50kΩ/RG (COS128). Leave open (NC) for unity gain. |
| 2 | VIN- | input | Inverting (negative) analog input to the instrumentation amplifier. Diode-clamped to the supply rails; input signals exceeding rails by >0.5V should be current-limited to ≤10mA. Bias current ±2nA typ. |
| 3 | VIN+ | input | Non-inverting (positive) analog input to the instrumentation amplifier. Diode-clamped to supply rails; input signals exceeding rails by >0.5V should be current-limited to ≤10mA. Bias current ±2nA typ. |
| 4 | -VS | power_in | Negative power supply pin. Operating range ±2.25V to ±18V (dual supply) or ground for single-supply operation. Bypass to ground with a 0.1µF ceramic capacitor close to the pin. |
| 5 | REF | input | Reference input pin. Sets the DC offset of the output; must be driven by a low-impedance source or tied to ground. Series resistance as small as 8Ω degrades CMR to ~80dB. |
| 6 | VOUT | output | Amplifier output. Swings to within 1.1V of each supply rail with ±10mA typical load current; short-circuit current ±24mA. Output = G × (VIN+ − VIN−) + VREF. |
| 7 | +VS | power_in | Positive power supply pin. Operating range ±2.25V to ±18V dual, or +4.5V to +36V single supply. Bypass with a 0.1µF ceramic capacitor close to the pin; 2.2µF tantalum optional for better performance. Quiescent current 1.0mA typ. |
| 8 | RG | passive | Gain setting pin. Connect an external gain resistor RG between pin 1 and pin 8 to set voltage gain G = 1 + 50kΩ/RG (COS128). Leave open (NC) for unity gain. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | COSINE |
| Package | SOP-8 |
| Category | Op-amp/Cmp |
| Pins | 8 |

## Ordering variants

Same part, different packaging or reel option.

- `COS128UAU`
- `COS128UA`
- `COS128UAC`
- `COS128UAP`
- `COS128UAPA`

## 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 | -125 | 25 | 125 | μV |  | 3 |
| Input Offset Voltage Drift | ΔVOS/ΔT |  | 0.2 | 1 | μV/°C | -40 to 125°C | 3 |
| Input Bias Current | IB | -10 | 2 | 10 | nA |  | 3 |
| Input Offset Current | IOS | -10 | 1 | 10 | nA |  | 3 |
| Common-Mode Rejection Ratio | CMRR | 125 |  |  | dB | G=100 | 3 |
| Gain Range | GR | 1 |  | 10000 | V/V |  | 4 |
| Gain Error | GE | -2 |  | 2 | % |  | 4 |
| Output Current | IOUT | -10 |  | 10 | mA | VDROPOUT < 1.2 V | 4 |
| Short-Circuit Current | ISC | -24 |  | 24 | mA |  | 4 |
| Operating Voltage Range |  | 2.25 |  | 18 | V |  | 4 |
| Power Supply Rejection Ratio | PSRR | 120 |  |  | dB |  | 4 |
| Quiescent Current / Amplifier | IQ |  | 1 | 1.5 | mA |  | 4 |
| Gain Bandwidth Product | GBWP |  | 1.5 |  | MHz | CL=100pF, RL=10kΩ | 4 |
| Slew Rate | SR |  | 1 |  | V/μs | CL=100pF, RL=10kΩ, Av=1 | 4 |
| Voltage Noise Density | en |  | 8 |  | nV/√Hz | f=1kHz | 4 |
| Power Supply Voltage (absolute max, +Vs to -Vs) |  |  |  | 36 | V |  | 2 |
| Differential Input Voltage Range |  | -36 |  | 36 | V |  | 2 |
| Output Current |  |  |  | 50 | mA |  | 2 |
| Storage Temperature Range |  | -65 |  | 150 | °C |  | 2 |
| Junction Temperature |  |  |  | 150 | °C |  | 2 |
| Operating Temperature Range |  | -40 |  | 125 | °C |  | 2 |
| ESD Susceptibility, HBM |  |  |  | 2000 | V |  | 2 |
| DC Supply Voltage |  | 2.5 |  | 18 | V |  | 3 |
| Operating ambient temperature |  | -40 |  | 125 | °C |  | 3 |
| Package Thermal Resistance, junction-to-ambient (SOP8) | RθJA |  | 155 |  | °C/W | SOP8 package | 3 |

## CAD (KiCad official)

- Symbol: `COS128UA`
- Footprint: `Package_SO:SOIC-8_3.9x4.9mm_P1.27mm`
- 3D model: SOP-8 (KiCad packages3D, STEP)
- 3D model files: `cos128ua-etched.step` / `cos128ua-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `cos128ua.step` / `cos128ua.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [COSINE datasheet](docs/cos128ua-datasheet.pdf) (8 pp, sha256 `e35a1a4eec057f26`, 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/cos128ua-datasheet.pdf)