# LM3404MRX

**Texas Instruments** · LED Drivers · SOP-8-EP

LM3404MRX from Texas Instruments, in a SOP-8-EP. 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 | SW | output | Switch pin connected to output inductor and Schottky diode. |
| 2 | BOOT | output | MOSFET drive bootstrap pin; connect 10-nF ceramic capacitor from this pin to SW. |
| 3 | DIM | input | PWM dimming input pin; logic-level PWM signal enables/disables power MOSFET and controls LED array light output. |
| 4 | GND | power_in | Ground pin connected to system ground. |
| 5 | CS | input | Current sense feedback pin; set LED array current by connecting resistor from this pin to ground. |
| 6 | RON | input | On-time control pin; resistor from this pin to VIN sets regulator controlled on-time. |
| 7 | VCC | power_out | Output of internal 7-V linear regulator; bypass to ground with minimum 0.1-µF ceramic capacitor (X5R or X7R dielectric). |
| 8 | VIN | power_in | Input voltage pin with nominal operating range 6 V to 42 V (LM3404) or 6 V to 75 V (LM3404HV). |
| 9 | EP | passive | Exposed pad (from the footprint; not named in the datasheet pin table). |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Texas Instruments |
| Package | SOP-8-EP |
| Category | LED Drivers |
| Pins | 9 |

## CAD (KiCad official)

- Symbol: `LM3404MRX`
- Footprint: `Package_SO:SOIC-8-1EP_3.9x4.9mm_P1.27mm_EP2.29x3mm`
- 3D model: SOP-8-EP (KiCad packages3D, STEP)
- 3D model files: `lm3404mrx-etched.step` / `lm3404mrx-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `lm3404mrx.step` / `lm3404mrx.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/lm3404) (47 pp, sha256 `c30b6b258c57c07a`, retrieved 2026-10-03, tier: lcsc)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-haiku-4-5-20251001` (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/lm3404mrx-datasheet.pdf)