# U0138

**UNI SEMIC** · DC-DC Converters · SOT-23-6

U0138 from UNI SEMIC, in a SOT-23-6. 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 | BS | power_out | Bootstrap pin: a capacitor connected between SW and BS is required to form a floating supply across the high-side switch driver. |
| 2 | GND | power_in | Ground pin. |
| 3 | FB | input | Adjustable-version feedback input; connect FB to the center point of the external resistor divider (regulated feedback voltage 0.78V to 0.82V, 0.80V typical). |
| 4 | EN | input | Drive to a logic-high to enable the IC and to a logic-low to disable it and enter micro-power shutdown mode (EN rising threshold 1.05V to 1.25V). |
| 5 | IN | power_in | Power supply pin; input voltage range is 4V to 30V. |
| 6 | SW | output | Switching pin; the switch node, with VSW limited to -0.3V to (VIN+0.5)V. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | UNI SEMIC |
| Package | SOT-23-6 |
| Category | Power Management (PMIC) |
| Pins | 6 |

## 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 Voltage Range |  | 4 |  | 30 | V |  | 4 |
| Supply Current in Operation |  |  | 0.4 | 0.6 | mA | VEN=3.0V, VFB=1.1V | 4 |
| Supply Current in Shutdown |  |  |  | 4 | μA | VEN =0 or EN = GND | 4 |
| Regulated Feedback Voltage |  | 0.78 | 0.8 | 0.82 | V | TA = 25°C, 4V≤VIN ≤18V | 4 |
| High-Side Switch Leakage Current |  |  |  | 1 | uA | VEN=0V, VSW=12V | 4 |
| Oscillation Frequency |  | 1.2 | 1.4 | 1.6 | MHz |  | 4 |
| Maximum Duty Cycle |  | 90 | 95 |  | % | VFB=0.807V | 4 |
| EN up Threshold |  | 1.05 | 1.15 | 1.25 | V | VEN-Rising | 4 |
| VIN, EN Voltage |  | -0.3 |  | 36 | V |  | 4 |
| VSW Voltage |  | -0.3 |  |  | V |  | 4 |
| VFB Voltages |  | -0.3 |  | 6 | V |  | 4 |
| Operating Temperature Range |  | -40 |  | 85 | °C |  | 4 |
| Storage Temperature Range |  | -65 |  | 150 | °C |  | 4 |
| Lead Temperature (Soldering, 10s) |  |  |  | 300 | °C | Soldering, 10s | 4 |
| Junction Temperature |  |  |  | 125 | °C |  | 4 |
| ESD (Human Body Model) | HMB |  |  | 2 | KV |  | 4 |
| ESD (Machine Model) | MM |  |  | 200 | V |  | 4 |
| Thermal Resistance Junction to Ambient | RθJA |  | 105 |  | °C/W |  | 4 |
| Thermal Resistance Junction to Case | RθJC |  | 35 |  | °C/W |  | 4 |

## CAD (KiCad official)

- Symbol: `U0138`
- Footprint: `Package_TO_SOT_SMD:SOT-23-6`
- 3D model: SOT-23-6 (KiCad packages3D, STEP)
- 3D model files: `u0138-etched.step` / `u0138-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `u0138.step` / `u0138.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [UNI SEMIC datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8756967968963989504) (12 pp, sha256 `660dc3b5becdd2c3`, retrieved 2026-10-19, 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/u0138-datasheet.pdf)