# ETA3421S2F

**etasolution** · LED Drivers · SOT23-5

ETA3421S2F from etasolution, in a SOT23-5. 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 | EN | input | Enable pin: drive high to enable the part and low to disable it, defaults to low when floating, and it doubles as the PWM dimming input at 20-100KHz. |
| 2 | GND | power_in | Ground return for the device. |
| 3 | SW | output | Inductor connection that drives the switching node, connected between SW and the regulator output; SW leakage is 5 µA max at VIN=5.5V with VSW=0 or 5.5V and EN=GND. |
| 4 | VIN | power_in | Supply voltage input over the 3.3V to 5.5V range, to be bypassed with a 10µF ceramic capacitor to GND. |
| 5 | FB | input | LED current feedback input: connect an external resistor from FB to GND to set ILED = 0.1/RS (A), with the FB regulation reference at 0.1V. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | etasolution |
| Package | SOT23-5 |
| Category | LED Drivers |
| 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 |
|---|---|---|---|---|---|---|---|
| VIN, EN, SW Voltage |  | -0.3 |  | 7.5 | V |  | 2 |
| FB Voltage |  | -0.3 |  | 6 | V |  | 2 |
| Operating Temperature Range |  | -40 |  | 85 | °C |  | 2 |
| Storage Temperature Range |  | -55 |  | 150 | °C |  | 2 |
| Input Voltage Range |  | 3.3 |  | 5.5 | V |  | 2 |
| Input UVLO Rising |  |  | 2.35 | 2.45 | V | Rising, Hysteresis=300mV | 2 |
| Input Supply Current |  |  | 35 | 50 | µA | VFB=0.65V, no switching | 2 |
| Input Shutdown Current |  |  | 2 | 5 | µA | VEN=0V | 2 |
| FB Input Current |  |  | 0.01 | 1 | µA | VFB=1V | 2 |
| PWM Dimming Frequency |  | 20 |  | 100 | KHz |  | 2 |
| Dimming Duty Cycle |  | 30 |  | 100 | % |  | 2 |
| EN Input Current |  |  | 1 | 2 | µA | VEN=5V | 2 |
| OVP Rising |  |  | 7 |  | V | Rising, Hysteresis=400mV | 2 |
| Thermal Shutdown |  |  | 160 |  | °C | Hysteresis=20°C | 2 |
| FB Voltage |  |  | 0.1 |  | V | 3.3V≤VIN≤5.5V | 2 |
| Switching Frequency |  |  | 1.5 |  | MHz |  | 2 |
| PMOS Switch On Resistance |  |  | 200 |  | mΩ | ISW=200mA | 2 |
| NMOS Switch On Resistance |  |  | 180 |  | mΩ | ISW=200mA | 2 |
| High Side Current Limit |  |  | 1.1 |  | A |  | 2 |
| SW Leakage Current |  |  | 5 |  | µA | VIN=5.5V, VSW=0 or 5.5V, EN= GND | 2 |
| EN Logic High Threshold |  |  | 1.2 |  | V | Rising | 2 |
| EN Logic Low Threshold |  |  | 0.4 |  | V | Falling | 2 |

## CAD (KiCad official)

- Symbol: `ETA3421S2F`
- Footprint: `Package_TO_SOT_SMD:SOT-23-5`
- 3D model: SOT23-5 (KiCad packages3D, STEP)
- 3D model files: `eta3421s2f-etched.step` / `eta3421s2f-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `eta3421s2f.step` / `eta3421s2f.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [etasolution datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8603065854636670976) (9 pp, sha256 `a935e4baaa0cfaa9`, 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/eta3421s2f-datasheet.pdf)