# UM803MS

**Union Semiconductor** · Supervisor And Reset ICs · SOT23-3

UM803MS from Union Semiconductor, in a SOT23-3. 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 | GND | power_in | Ground reference for the supply. |
| 2 | RESET | output | Active-low open-drain reset output that remains low while VCC is below the reset threshold and for at least 140ms after VCC rises above it, requiring a pull-up resistor to any supply between 0 and 6V. |
| 3 | VCC | power_in | Supply voltage input for +5V, +3.3V, +3V or +2.5V systems, with absolute maximum of -0.3 to +6.0V. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Union Semiconductor |
| Package | SOT23-3 |
| Category | Power Management (PMIC) |
| Pins | 3 |

## Electrical characteristics

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

| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| Supply Voltage Range | VCC | 1 |  | 5.5 | V | TA=0°C to +70°C | 5 |
| Supply Current | ICC |  |  | 2 | μA |  | 5 |
| Reset Threshold M Version | VTH | 4.31 | 4.38 | 4.45 | V | TA=+25°C | 5 |
| Reset Threshold M Version | VTH | 4.25 |  | 4.5 | V | TA=-40°C to +85°C | 5 |
| Reset Active Timeout Period | tRP | 140 | 240 | 560 | ms |  | 5 |
| RESET Output Voltage Low | VOL |  |  | 0.4 | V | VCC=VTH min, ISINK=3.2mA, UM803L_/M_/J_ | 5 |
| RESET Output Voltage Low | VOL |  |  | 0.3 | V | VCC>1.0V, ISINK=50μA | 5 |
| RESET Open-Drain Output Leakage Current |  |  |  | 1 | μA | VCC>VTH, RESET Deasserted | 5 |
| Reset Threshold Tempco |  |  | 150 |  | ppm/°C |  | 5 |
| VCC to Reset Delay |  |  | 10 |  | μs | VCC=VTH to (VTH-100mV) | 5 |
| Supply Voltage | VCC | -0.3 |  | 6 | V |  | 4 |
| RESET Voltage | RESET | -0.3 |  | 6 | V |  | 4 |
| Input Current, VCC | ICC |  |  | 20 | mA |  | 4 |
| Output Current, RESET | IO |  |  | 20 | mA |  | 4 |
| Rate of Rise, VCC |  |  |  | 100 | V/μs |  | 4 |
| Continuous Power Dissipation SOT23-3 | PD |  |  | 320 | mW | Derate 4mW/°C above 70°C | 4 |
| Operating Temperature Range SOT23-3 | TA | -40 |  | 105 | °C | SOT23-3 | 4 |
| Storage Temperature Range | TSTG | -65 |  | 150 | °C |  | 4 |
| Lead Temperature (Soldering, 10s) |  |  |  | 300 | °C |  | 4 |

## CAD (KiCad official)

- Symbol: `UM803MS`
- Footprint: `Package_TO_SOT_SMD:SOT-23-3`
- 3D model: SOT23-3 (KiCad packages3D, STEP)
- 3D model files: `um803ms-etched.step` / `um803ms-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `um803ms.step` / `um803ms.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Union Semiconductor datasheet](docs/um803ms-datasheet.pdf) (12 pp, sha256 `064b0eaa669a8ef8`, retrieved 2026-10-22, tier: lcsc)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-sonnet-5-5` (text+vision), consensus `claude-opus-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/um803ms-datasheet.pdf)