# TPSY8121BABC

**TECH PUBLIC** · DC-DC Converters · SOT-23-6

TPSY8121BABC from TECH PUBLIC, in a SOT-23-6. Pinout and pin descriptions extracted from the manufacturer datasheet by ds2sf; symbol, footprint, and 3D from KiCad-official CAD.

## Pinout

| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | BS | passive | Boot-strap pin. Supplies the high-side gate driver. Decouple this pin to LX with a 100nF (0.1uF) ceramic capacitor. |
| 2 | GND | power_in | Ground pin. Device return; tie to the system ground plane with a short, low-impedance connection. |
| 3 | FB | input | Output feedback pin. Connect to the center tap of the output resistor divider to program Vout = 0.6 V × (1 + R1/R2). Internal reference is 0.6V (±2%). |
| 4 | EN | input | Enable control input. Pull high (VIH ≥ 2V) to turn the regulator on, pull low (≤ 0.5V) to shut down. Do not float. |
| 5 | IN | power_in | Input supply pin (4.5V to 20V). Decouple to GND with at least a 1uF (typ. 4.7uF X5R) ceramic capacitor placed as close to the IN and GND pins as possible. |
| 6 | LX | power_out | Switching node / inductor pin. Connects to the source of the internal high-side FET and drain of the low-side FET; connect to the switching node of the output inductor. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | TECH PUBLIC |
| Package | SOT-23-6 |
| Category | PMIC |
| Pins | 6 |

## Ordering variants

Same part, different packaging or reel option.

- `TPSY8121BABC`

## CAD (KiCad official)

- Symbol: `TPSY8121BABC`
- Footprint: `Package_TO_SOT_SMD:SOT-23-6`
- 3D model: SOT-23-6 (KiCad packages3D, STEP)
- 3D model files: `tpsy8121babc-etched.step` / `tpsy8121babc-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `tpsy8121babc.step` / `tpsy8121babc.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [TECH PUBLIC datasheet](docs/tpsy8121babc-datasheet.pdf) (7 pp, sha256 `53b5795b53ca7410`, retrieved 2026-08-17, tier: lcsc)
- **Extractor:** `ds2sf` (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
- **CAD:** KiCad official libraries (CC-BY-SA 4.0).

[Datasheet PDF](docs/tpsy8121babc-datasheet.pdf)