# LM4050QAEM3X4.1

**Texas Instruments** · Voltage Reference · SOT-23-3

LM4050QAEM3X4.1 from Texas Instruments, in a SOT-23-3. 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 | Cathode | bidirectional | Cathode pin carries the shunt current and serves as the input voltage terminal, with current set by the external series resistor RS. |
| 2 | Anode | power_in | Anode is the general-purpose pin, normally connected to ground, and forms a parasitic Schottky diode with pin 3 in the SOT-23 package. |
| 3 | NC | unconnected | No internal connection; it must be left floating or tied to pin 2, and TI recommends tying it to the anode in applications with high EMI or significant high-frequency switching noise. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Texas Instruments |
| Package | SOT-23-3 |
| 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 |
|---|---|---|---|---|---|---|---|
| Reverse breakdown voltage tolerance (A grade, 25°C) | VR | -4.1 |  | 4.1 | mV | IR = 100μA | 8 |
| Reverse breakdown voltage tolerance (A grade, extended temperature range) | VR | -25 |  | 25 | mV | TA = TJ = TMIN to TMAX, extended temperature range, IR = 100μA | 8 |
| Minimum operating current | IRMIN |  | 52 | 68 | μA | TA = TJ = 25°C | 8 |
| Minimum operating current (extended temperature range) | IRMIN |  |  | 78 | μA | TA = TJ = TMIN to TMAX, extended temperature range | 8 |
| Average reverse breakdown voltage temperature coefficient | ΔVR/ΔT | -30 |  | 30 | ppm/°C | IR = 10mA | 8 |
| Average reverse breakdown voltage temperature coefficient | ΔVR/ΔT | -20 |  | 20 | ppm/°C | IR = 1mA | 8 |
| Average reverse breakdown voltage temperature coefficient | ΔVR/ΔT | -50 |  | 50 | ppm/°C | IR = 100μA, TA = TJ = TMIN to TMAX | 8 |
| Reverse breakdown voltage change with operating current | ΔVR/ΔIR |  | 0.2 | 0.9 | mV | IRMIN ≤ IR ≤ 1mA, TA = TJ = 25°C | 8 |
| Reverse breakdown voltage change with operating current | ΔVR/ΔIR |  |  | 1.2 | mV | IRMIN ≤ IR ≤ 1mA, TA = TJ = TMIN to TMAX | 8 |
| Reverse breakdown voltage change with operating current | ΔVR/ΔIR |  | 2 | 7 | mV | 1mA ≤ IR ≤ 15mA, TA = TJ = 25°C | 8 |
| Reverse breakdown voltage change with operating current | ΔVR/ΔIR |  |  | 10 | mV | 1mA ≤ IR ≤ 15mA, TA = TJ = TMIN to TMAX | 8 |
| Reverse dynamic impedance | ZR |  | 0.5 |  | Ω | IR = 1mA, f = 120Hz, IAC = 0.1 IR | 8 |
| Wideband noise | eN |  | 93 |  | μVrms | IR = 100μA, 10Hz ≤ f ≤ 10kHz | 8 |
| Long-term stability of reverse breakdown voltage | ΔVR |  | 120 |  | ppm | t = 1000 hours, T = 25°C ± 0.1°C, IR = 100μA | 8 |
| Thermal hysteresis | VHYST |  | 1.148 |  | mV | ΔT = -40°C to 125°C | 8 |
| Reverse breakdown voltage | VR |  | 4.096 |  | V | IR = 100μA | 8 |
| Reverse current |  |  |  | 20 | mA |  | 4 |
| Forward current |  |  |  | 10 | mA |  | 4 |
| Power dissipation |  |  |  | 280 | mW | TA = 25°C | 4 |
| Maximum junction temperature |  |  |  | 150 | °C |  | 4 |
| Storage temperature |  | -65 |  | 150 | °C |  | 4 |
| ESD human body model | V(ESD) | -2000 |  | 2000 | V | HBM per ANSI/ESDA/JEDEC JS-001 | 4 |
| ESD charged device model | V(ESD) | -500 |  | 500 | V | CDM per JEDEC JESD22-C101 | 4 |
| Ambient temperature range (extended) |  | -40 |  | 125 | °C | Extended temperature range, natural ventilation | 5 |
| Junction temperature range (extended) |  | -40 |  | 125 | °C | Extended temperature range | 5 |
| Junction-to-ambient thermal resistance | RθJA |  | 287 |  | °C/W | DBZ (SOT-23) 3-pin | 5 |
| Junction-to-case (top) thermal resistance | RθJC(top) |  | 106.6 |  | °C/W | DBZ (SOT-23) 3-pin | 5 |
| Junction-to-board thermal resistance | RθJB |  | 57.7 |  | °C/W | DBZ (SOT-23) 3-pin | 5 |
| Junction-to-top characterization parameter | ψJT |  | 5.5 |  | °C/W | DBZ (SOT-23) 3-pin | 5 |
| Junction-to-board characterization parameter | ψJB |  | 56.4 |  | °C/W | DBZ (SOT-23) 3-pin | 5 |

## CAD (KiCad official)

- Symbol: `LM4050QAEM3X4.1`
- Footprint: `Package_TO_SOT_SMD:SOT-23-3`
- 3D model: SOT-23-3 (KiCad packages3D, STEP)
- 3D model files: `lm4050qaem3x4-1-etched.step` / `lm4050qaem3x4-1-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `lm4050qaem3x4-1.step` / `lm4050qaem3x4-1.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [Texas Instruments datasheet](https://www.ti.com/cn/lit/gpn/lm4050-n-q1) (47 pp, sha256 `02a99aa1f022863b`, retrieved 2026-11-05, tier: manufacturer)
- **Datasheet language:** Chinese. Pin names, descriptions, and specs on this page were extracted and translated to English by ds2sf; the linked PDF is the manufacturer original.
- **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/lm4050qaem3x4-1-datasheet.pdf)