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LP3981S-33B5F
Public Made by Adomby adom
LOWPOWER Voltage Regulators - Linear, Low Drop Out (LDO) Regulators, SOT-23-5. Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.
3D Model
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Symbol & Footprint
Schematic Symbol
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PCB Footprint
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Datasheet
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README
markdownLP3981S-33B5F
LOWPOWER · Voltage Regulators - Linear, Low Drop Out (LDO) Regulators · SOT-23-5
LP3981S-33B5F from LOWPOWER, in a SOT-23-5. 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 | power_in | Power supply input pin; the datasheet recommends a supply input voltage of 2.5V to 5.5V and an under-voltage lockout threshold typically 1.5V. |
| 2 | GND | power_in | Ground reference pin for the regulator. |
| 3 | EN | input | Active-high chip enable input with an EN input voltage range of 0V to 5.5V and logic thresholds of 0.4V (low) and 1.4V (high); the pin is high impedance, so a 100kΩ pull-down to GND is recommended when the control signal is floating. |
| 4 | NC | unconnected | No connection; the datasheet lists this pin as NC. |
| 5 | OUT | power_out | Regulated output pin rated for 300mA output current (500mA peak) when VIN is above 2.8V, with an internal 120Ω active pull-down to GND that discharges the output when EN is logic low or in thermal shutdown. |
Key specifications
| Parameter | Value |
|---|---|
| Manufacturer | LOWPOWER |
| Package | SOT-23-5 |
| Category | Power Management (PMIC) |
| Pins | 5 |
Electrical characteristics
Limits as printed in the datasheet (page.json metadata.characteristics carries them as data).
| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| Output Voltage Accuracy | ΔVOUT | -1 | 1 | % | IOUT=1mA | 4 | |
| Supply Input Voltage | VIN | 2.5 | 5.5 | V | 3 | ||
| EN Input Voltage | VEN | 0 | 5.5 | V | 3 | ||
| Operation Junction Temperature Range | TJ | -20 | 125 | ℃ | 3 | ||
| Operation Ambient Temperature Range | TA | -40 | 85 | ℃ | 3 | ||
| Supply Input Voltage (absolute maximum) | VIN | -0.3 | 6 | V | 3 | ||
| Other Pins Voltage | -0.3 | 6 | V | 3 | |||
| Power Dissipation SOT23-5 | PD | 400 | mW | TA=25℃, SOT23-5 | 3 | ||
| Storage Temperature Range | -65 | 150 | ℃ | 3 | |||
| Lead Temperature (Soldering) | 260 | ℃ | 10 sec. | 3 | |||
| ESD HBM (Human Body Model) | 2 | KV | 3 | ||||
| ESD MM (Machine Model) | 200 | V | 3 | ||||
| Standby Current | ISTBY | 0.1 | 1 | μA | VEN=0V, Shutdown | 4 | |
| EN Input Bias Current | IIBSD | 0.6 | 2 | μA | VEN=1V | 4 | |
| Output Current | Iout | 300 | mA | VIN>2.8V | 4 | ||
| Current Limit | ILIM | 550 | mA | RLOAD=1Ω | 4 | ||
| Quiescent Current | IQ | 58 | μA | (VOUT+1V)<VIN<5.5V, VOUT=3.3V | 4 | ||
| Dropout Voltage | VDROP | 260 | mV | IOUT=300mA, VOUT=3.3V | 4 | ||
| Line Regulation | ΔVOUT/(ΔVIN×VOUT) | 0.5 | % | VOUT=3.3V, IOUT=1mA, VIN=4.3V to 5.5V | 4 | ||
| Load Regulation | ΔVOUT/VOUT | 1 | % | VOUT=3.3V, IOUT=1mA to 200mA | 4 | ||
| EN Logic-Low Voltage | VIL | 0.4 | V | VIN=(VOUT+1V) to 5.5V, Shutdown | 4 | ||
| EN Logic-High Voltage | VIH | 1.4 | V | VIN=(VOUT+1V) to 5.5V, Start-Up | 4 | ||
| Output Noise Voltage | 100 | μVRMS | 10Hz to 100kHz, IOUT=200mA, COUT=1µF | 4 | |||
| Power Supply Rejection Rate (1 kHz) | PSRR | -63 | dB | f=1KHz, COUT=1µF, IOUT=50mA, VOUT=3.3V | 4 | ||
| Power Supply Rejection Rate (10 kHz) | PSRR | -56 | dB | f=10kHz, COUT=1µF, IOUT=50mA, VOUT=3.3V | 4 | ||
| Thermal Shutdown Temperature | TSD | 160 | ℃ | IOUT=0.1mA | 4 | ||
| Package Thermal Resistance SOT23-5 | θJA | 250 | ℃/W | SOT23-5 | 3 |
CAD (KiCad official)
- Symbol:
LP3981S-33B5F - Footprint:
Package_TO_SOT_SMD:SOT-23-5 - 3D model: SOT-23-5 (KiCad packages3D, STEP)
- 3D model files:
lp3981s-33b5f-etched.step/lp3981s-33b5f-etched.glbcarry the MPN laser-etched on the die in a toggleableAdom.LaserEtchgroup (Fusion-ready);lp3981s-33b5f.step/lp3981s-33b5f.glbare the bare package body.
Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- Datasheet: LOWPOWER datasheet (7 pp, sha256
87a0e6202ae5fcdb, retrieved 2026-10-19, 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).