component
U0349
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UNI SEMIC DC-DC Converters, ESOP-8. Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.
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U0349
UNI SEMIC · DC-DC Converters · ESOP-8
U0349 from UNI SEMIC, in a ESOP-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 | BS | power_out | Bootstrap pin: a capacitor connected between SW and BST forms the floating supply for the high-side switch driver, with BS voltage limited to -0.3 V to Vsw+5 V. |
| 2 | IN | power_in | Power supply input; the recommended operating input voltage range is 4.5 V to 38 V, with an absolute maximum VIN of 42 V. |
| 3 | SW | output | Switching node connecting the internal power MOSFETs to the inductor; SW voltage is limited to -0.3 V to VIN+1 V (-5 V to VIN+2 V for 10 ns transients). |
| 4 | GND | power_in | Ground pin, to be connected to a large copper area for heat dissipation. |
| 5 | FB | input | Adjustable-version feedback input, connected to the center point of the external resistor divider; the feedback voltage is 0.923 V typical (0.900 V to 0.946 V) and the absolute maximum is 6 V. |
| 6 | NC | unconnected | No connection. |
| 7 | EN | input | Enable input: drive to logic-high (above 1.1 V rising threshold) to enable the IC, and to logic-low (below 0.9 V falling threshold) to disable it into micro-power shutdown mode. |
| 8 | NC | unconnected | No connection. |
| 9 | EPAD | power_in | Exposed thermal pad, listed with GND as "4/9" in the pin table, to be connected to a large copper area for thermal performance. |
Key specifications
| Parameter | Value |
|---|---|
| Manufacturer | UNI SEMIC |
| Package | ESOP-8 |
| Category | Power Management (PMIC) |
| Pins | 9 |
Electrical characteristics
Limits as printed in the datasheet (page.json metadata.characteristics carries them as data).
| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| Operating junction temperature | -40 | 125 | °C | 4 | |||
| Operating temperature range | -40 | 85 | °C | 4 | |||
| Input voltage | VIN | 4.5 | 38 | V | 4 | ||
| Output current | 0 | 2 | A | 4 | |||
| VIN voltage | VIN | -0.3 | 42 | V | 4 | ||
| EN voltage | -0.3 | 42 | V | 4 | |||
| SW voltage | -0.3 | V | Printed max VIN+1V | 4 | |||
| SW voltage (10ns transient) | -5 | V | 10ns transient; printed max VIN+2V | 4 | |||
| BS voltage | -0.3 | V | Printed max Vsw+5V | 4 | |||
| FB voltage | -0.3 | 6 | V | 4 | |||
| Operating junction temperature | TJ | -40 | 150 | °C | 4 | ||
| Storage temperature | Tstg | -55 | 150 | °C | 4 | ||
| Lead temperature (soldering) | 260 | °C | Soldering, 10 sec. | 4 | |||
| ESD Human Body Model | V(ESD-HBM) | -2000 | 2000 | V | ANSI/ESDA/JEDEC JS-001-2014, Class 2 | 4 | |
| ESD Charged Device Model | V(ESD-CDM) | -200 | 200 | V | ANSI/ESDA/JEDEC JS-002-2014, Class C0b | 4 | |
| Latch-up | ILATCH-UP | -150 | 150 | mA | JEDEC STANDARD NO.78E, Class I | 4 | |
| Input Voltage Range | 4.5 | 38 | V | 5 | |||
| Supply Current (Quiescent) | 0.6 | 0.8 | mA | VEN =3.0V | 5 | ||
| Supply Current (Shutdown) | 4 | uA | VEN =0 or EN = GND | 5 | |||
| Feedback Voltage | 0.9 | 0.923 | 0.946 | V | 5 | ||
| Valley Switch Current Limit | 4 | A | 5 | ||||
| EN Rising Threshold | 1.1 | V | 5 | ||||
| EN Falling Threshold | 0.9 | V | 5 | ||||
| Under-Voltage Lockout Threshold Wake up VIN Voltage | 3.8 | 4.1 | V | 5 | |||
| Under-Voltage Lockout Threshold Shutdown VIN Voltage | 3.2 | 3.5 | V | 5 | |||
| Junction-to-ambient thermal resistance | RθJA | 48.7 | °C/W | JESD 51-7, 4-layer JEDEC board | 5 | ||
| Junction-to-case (top) thermal resistance | RθJC(top) | 52.4 | °C/W | 5 | |||
| Junction-to-board thermal resistance | RθJB | 25.5 | °C/W | 5 | |||
| Junction-to-top characterization parameter | ψJT | 8.4 | °C/W | 5 | |||
| Junction-to-board characterization parameter | ψJB | 25.2 | °C/W | 5 | |||
| Junction-to-case (bottom) thermal resistance | θJCbot | 6.5 | °C/W | 5 |
CAD (KiCad official)
- Symbol:
U0349 - Footprint:
Package_SO:SOIC-8-1EP_3.9x4.9mm_P1.27mm_EP2.41x3.3mm - 3D model: ESOP-8 (KiCad packages3D, STEP)
- 3D model files:
u0349-etched.step/u0349-etched.glbcarry the MPN laser-etched on the die in a toggleableAdom.LaserEtchgroup (Fusion-ready);u0349.step/u0349.glbare the bare package body.
Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- Datasheet: UNI SEMIC datasheet (14 pp, sha256
2c3df820105e0479, retrieved 2026-10-18, tier: lcsc) - Extractor: parts-factory
2.0.0/extract_pins 0.3, primaryclaude-haiku-5-5(text), consensusclaude-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).
# U0349
**UNI SEMIC** · DC-DC Converters · ESOP-8
U0349 from UNI SEMIC, in a ESOP-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 | BS | power_out | Bootstrap pin: a capacitor connected between SW and BST forms the floating supply for the high-side switch driver, with BS voltage limited to -0.3 V to Vsw+5 V. |
| 2 | IN | power_in | Power supply input; the recommended operating input voltage range is 4.5 V to 38 V, with an absolute maximum VIN of 42 V. |
| 3 | SW | output | Switching node connecting the internal power MOSFETs to the inductor; SW voltage is limited to -0.3 V to VIN+1 V (-5 V to VIN+2 V for 10 ns transients). |
| 4 | GND | power_in | Ground pin, to be connected to a large copper area for heat dissipation. |
| 5 | FB | input | Adjustable-version feedback input, connected to the center point of the external resistor divider; the feedback voltage is 0.923 V typical (0.900 V to 0.946 V) and the absolute maximum is 6 V. |
| 6 | NC | unconnected | No connection. |
| 7 | EN | input | Enable input: drive to logic-high (above 1.1 V rising threshold) to enable the IC, and to logic-low (below 0.9 V falling threshold) to disable it into micro-power shutdown mode. |
| 8 | NC | unconnected | No connection. |
| 9 | EPAD | power_in | Exposed thermal pad, listed with GND as "4/9" in the pin table, to be connected to a large copper area for thermal performance. |
## Key specifications
| Parameter | Value |
|---|---|
| Manufacturer | UNI SEMIC |
| Package | ESOP-8 |
| Category | Power Management (PMIC) |
| Pins | 9 |
## Electrical characteristics
Limits as printed in the datasheet (page.json `metadata.characteristics` carries them as data).
| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| Operating junction temperature | | -40 | | 125 | °C | | 4 |
| Operating temperature range | | -40 | | 85 | °C | | 4 |
| Input voltage | VIN | 4.5 | | 38 | V | | 4 |
| Output current | | 0 | | 2 | A | | 4 |
| VIN voltage | VIN | -0.3 | | 42 | V | | 4 |
| EN voltage | | -0.3 | | 42 | V | | 4 |
| SW voltage | | -0.3 | | | V | Printed max VIN+1V | 4 |
| SW voltage (10ns transient) | | -5 | | | V | 10ns transient; printed max VIN+2V | 4 |
| BS voltage | | -0.3 | | | V | Printed max Vsw+5V | 4 |
| FB voltage | | -0.3 | | 6 | V | | 4 |
| Operating junction temperature | TJ | -40 | | 150 | °C | | 4 |
| Storage temperature | Tstg | -55 | | 150 | °C | | 4 |
| Lead temperature (soldering) | | | | 260 | °C | Soldering, 10 sec. | 4 |
| ESD Human Body Model | V(ESD-HBM) | -2000 | | 2000 | V | ANSI/ESDA/JEDEC JS-001-2014, Class 2 | 4 |
| ESD Charged Device Model | V(ESD-CDM) | -200 | | 200 | V | ANSI/ESDA/JEDEC JS-002-2014, Class C0b | 4 |
| Latch-up | ILATCH-UP | -150 | | 150 | mA | JEDEC STANDARD NO.78E, Class I | 4 |
| Input Voltage Range | | 4.5 | | 38 | V | | 5 |
| Supply Current (Quiescent) | | | 0.6 | 0.8 | mA | VEN =3.0V | 5 |
| Supply Current (Shutdown) | | | | 4 | uA | VEN =0 or EN = GND | 5 |
| Feedback Voltage | | 0.9 | 0.923 | 0.946 | V | | 5 |
| Valley Switch Current Limit | | 4 | | | A | | 5 |
| EN Rising Threshold | | 1.1 | | | V | | 5 |
| EN Falling Threshold | | | | 0.9 | V | | 5 |
| Under-Voltage Lockout Threshold Wake up VIN Voltage | | | 3.8 | 4.1 | V | | 5 |
| Under-Voltage Lockout Threshold Shutdown VIN Voltage | | 3.2 | 3.5 | | V | | 5 |
| Junction-to-ambient thermal resistance | RθJA | | 48.7 | | °C/W | JESD 51-7, 4-layer JEDEC board | 5 |
| Junction-to-case (top) thermal resistance | RθJC(top) | | 52.4 | | °C/W | | 5 |
| Junction-to-board thermal resistance | RθJB | | 25.5 | | °C/W | | 5 |
| Junction-to-top characterization parameter | ψJT | | 8.4 | | °C/W | | 5 |
| Junction-to-board characterization parameter | ψJB | | 25.2 | | °C/W | | 5 |
| Junction-to-case (bottom) thermal resistance | θJCbot | | 6.5 | | °C/W | | 5 |
## CAD (KiCad official)
- Symbol: `U0349`
- Footprint: `Package_SO:SOIC-8-1EP_3.9x4.9mm_P1.27mm_EP2.41x3.3mm`
- 3D model: ESOP-8 (KiCad packages3D, STEP)
- 3D model files: `u0349-etched.step` / `u0349-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `u0349.step` / `u0349.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/8604430090566713344) (14 pp, sha256 `2c3df820105e0479`, retrieved 2026-10-18, 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/u0349-datasheet.pdf)