# TX4137

**XDS** · DC-DC Converters · SOT-23-6

TX4137 from XDS, in a SOT-23-6. Pinout and pin descriptions extracted from the datasheet by ds2sf; symbol, footprint, and 3D from KiCad-official CAD.

## Pinout

| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | NC | unconnected | No connect. Leave floating. |
| 2 | GND | power_in | Ground reference for the IC. Connect to the system ground plane using a large copper area to improve thermal dissipation. |
| 3 | FB | input | Output feedback voltage pin. Connect to the mid-point of an external resistor divider from VOUT to GND. The internal reference is 0.812V (typ, 0.792-0.832V). Absolute max 6V. |
| 4 | EN | input | Chip enable input. Rising threshold ~1.35V, falling ~1.17V, hysteresis 180mV. Do not leave floating; pull up to IN through ~510kΩ if unused. Absolute max 6V. |
| 5 | IN | power_in | Chip power input. Operates from 5.5V to 60V (abs max 65V). Bypass with a low-ESR ceramic capacitor (X5R/X7R, typically 4.7µF) placed close to the pin. |
| 6 | SW | output | Switch node output; drain of the internal high-side power MOSFET (RDS(on) ≈ 0.9Ω). Connect to the inductor and to the freewheeling Schottky diode cathode. Operates from -0.3V to VIN+0.3V. |

## Key specifications

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

## Electrical characteristics

Limits as printed in the datasheet (page.json `metadata.characteristics` carries them as data).

| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| Feedback voltage | VFB | 0.792 | 0.812 | 0.832 | V | 4.5V < VIN < 60V | 4 |
| Current limit threshold | ILIM | 1 | 1.25 | 1.5 | A |  | 4 |
| Oscillator frequency | fSW | 400 | 500 | 600 | kHz | VFB = 0.6V | 4 |
| Minimum on time | τON | 100 |  |  | ns |  | 4 |
| Feedback current | IFB |  | 0.1 |  | μA | VFB = 0.85V | 4 |
| Switch on-resistance (internal MOSFET) | RDS(ON) |  | 0.9 |  | Ω |  | 4 |
| Switch leakage current | ISW_LKG |  | 1 |  | μA | VEN = 0V, VSW = 0V | 4 |
| Maximum duty cycle | DMAX |  | 95 |  | % | VFB = 0.6V | 4 |
| UVLO rising voltage | UUVLO_R |  | 5.5 |  | V |  | 4 |
| UVLO hysteresis voltage | UUVLO_HYS |  | 500 |  | mV |  | 4 |
| EN rising threshold | VEN_R |  | 1.35 |  | V |  | 4 |
| EN falling threshold | VEN_F |  | 1.17 |  | V |  | 4 |
| EN hysteresis threshold | VEN_HYS |  | 180 |  | mV |  | 4 |
| EN output current | IEN |  | 3.1 |  | μA | VEN = 2V | 4 |
| EN output current | IEN |  | 0.1 |  | μA | VEN = 0V | 4 |
| VIN shutdown current | IS |  | 3 |  | μA | VEN = 0V | 4 |
| VIN quiescent current | IQ |  | 0.7 | 0.8 | mA | VEN = 2V, VFB = 1V | 4 |
| Thermal shutdown temperature | TSD |  | 165 |  | °C |  | 4 |
| Thermal shutdown hysteresis | TSD_HYS |  | 20 |  | °C |  | 4 |
| IN pin operating voltage range (absolute maximum) | VIN | -0.3 |  | 65 | V |  | 3 |
| SW pin operating voltage range (absolute maximum) | VSW | -0.3 |  |  | V |  | 3 |
| EN and FB pin operating voltage range (absolute maximum) | Vmax | -0.3 |  | 6 | V |  | 3 |
| EN pin sink current (absolute maximum) | IEN_SINK |  |  | 100 | μA |  | 3 |
| Operating temperature range | TA | -40 |  | 125 | °C |  | 3 |
| SOT23-6 maximum power dissipation | PSOT23-6 |  |  | 0.25 | W |  | 3 |
| Storage temperature range | TSTG | -45 |  | 150 | °C |  | 3 |
| Soldering temperature (under 30 s) | TSD |  |  | 260 | °C | Time less than 30 s | 3 |
| ESD withstand voltage (human body model) | VESD |  |  | 2000 | V | Human body model | 3 |
| Input voltage range (product feature) | VIN | 5.5 |  | 60 | V |  | 1 |

## CAD (KiCad official)

- Symbol: `TX4137`
- Footprint: `Package_TO_SOT_SMD:SOT-23-6`
- 3D model: SOT-23-6 (KiCad packages3D, STEP)
- 3D model files: `tx4137-etched.step` / `tx4137-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `tx4137.step` / `tx4137.glb` are the bare package body.

## 3D model downloads

Two STEP files. Same geometry, different body top:

| File | Size | Use it when |
|---|---|---|
| [`tx4137.step`](tx4137.step) | 97 KB | You want the bare part, or you mark your own boards. |
| [`tx4137-etched.step`](tx4137-etched.step) | 1.1 MB | You want the part with `TX4137` already on it. |

The marking in the etched file is real recessed geometry cut into the solid, not a
texture or a decal: 285 faces against 117 in the bare model. It
survives export, section views, and rendering in any CAD tool, and it drops straight
into KiCad or Fusion with no extra setup.

## Provenance

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

- **Datasheet:** [XDS datasheet](docs/tx4137-datasheet.pdf) (8 pp, sha256 `977d631c3d6360a2`, 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/tx4137-datasheet.pdf)