# ETA3521FSG

**etasolution** · DC-DC Converters · SOT-563

ETA3521FSG from etasolution, in a SOT-563. 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 | GND | power_in | Ground reference pin for the regulator (PIN DESCRIPTION: 'Ground'). |
| 2 | SW | power_out | Inductor connection: connect an inductor between SW and the regulator output, with SW voltage rated -0.3V to 6.5V absolute maximum. |
| 3 | VIN | power_in | Supply voltage input operating from 2.5V to 6.0V, to be bypassed with a 22µF ceramic capacitor to GND. |
| 4 | EN | input | Enable pin, where a high voltage level enables the device (EN logic high threshold 1.2V rising, logic low 0.4V falling); for automatic start-up, connect EN to VIN through a pull-up resistor. |
| 5 | FB | input | Feedback input: an external resistor divider from the output to FB and GND sets VOUT, with FB voltage 0.594V to 0.606V (0.6V typical). |
| 6 | OUT | power_out | Output pin, to be bypassed with a 22µF or larger ceramic capacitor placed closely between this pin and GND. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | etasolution |
| Package | SOT-563 |
| Category | Power Management (PMIC) |
| Pins | 6 |

## CAD (KiCad official)

- Symbol: `ETA3521FSG`
- Footprint: `Package_TO_SOT_SMD:SOT-563`
- 3D model: SOT-563 (KiCad packages3D, STEP)
- 3D model files: `eta3521fsg-etched.step` / `eta3521fsg-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `eta3521fsg.step` / `eta3521fsg.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/8590909022201995264) (10 pp, sha256 `c984cf1a015ae538`, retrieved 2026-10-09, 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/eta3521fsg-datasheet.pdf)