component
LM3549SQX
Public Made by Adomby adom
Texas Instruments LED Drivers, WQFN-24-EP(4x4). Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.
3D Model
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Symbol & Footprint
Schematic Symbol
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PCB Footprint
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Datasheet
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README
markdownLM3549SQX
Texas Instruments · LED Drivers · WQFN-24-EP(4x4)
LM3549SQX from Texas Instruments, in a WQFN-24-EP(4x4). 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 | NC | unconnected | No internal connection on this pin. |
| 2 | L1 | passive | SMPS inductor positive terminal 1, connected to the 2.2 µH buck-boost inductor in the typical application circuit. |
| 3 | L1 | passive | SMPS inductor positive terminal 2, on the same L1 node as pin 2. |
| 4 | GND_SW | power_in | SMPS (buck-boost converter) ground. |
| 5 | L2 | passive | SMPS inductor negative terminal 1, on the L2 node of the buck-boost converter. |
| 6 | L2 | passive | SMPS inductor negative terminal 2, on the same L2 node as pin 5. |
| 7 | VOUT | power_out | Buck-boost converter output terminal 1. |
| 8 | NC | unconnected | No internal connection on this pin. |
| 9 | VOUT | power_out | Buck-boost converter output terminal 2, on the same VOUT node as pin 7. |
| 10 | R_EN | input | Red output enable input. |
| 11 | VDDS | power_in | Supply voltage pin; the datasheet's input voltage range is 2.7 V to 5.5 V. |
| 12 | G_EN | input | Green output enable input. |
| 13 | B_EN | input | Blue output enable input. |
| 14 | PWM | input | Master fader input; scales the total brightness of the LED outputs. |
| 15 | GND | power_in | Ground reference; all device voltages are referenced to the GND pin. |
| 16 | R_OUT | output | Red LED constant-current driver output. |
| 17 | G_OUT | output | Green LED constant-current driver output. |
| 18 | B_OUT | output | Blue LED constant-current driver output. |
| 19 | FAULT | output | Fault detection interrupt output; active LOW open-drain. |
| 20 | SDA | bidirectional | I2C data line. |
| 21 | SCL | input | I2C clock line. |
| 22 | EN | input | Enable input and I/O reference level. |
| 23 | VDDP | power_in | SMPS supply voltage pin. |
| 24 | NC | unconnected | No internal connection on this pin. |
| 25 | EP | passive | Exposed pad (from the footprint; not named in the datasheet pin table). |
Key specifications
| Parameter | Value |
|---|---|
| Manufacturer | Texas Instruments |
| Package | WQFN-24-EP(4x4) |
| Category | Nixie Tube Driver/LED Driver |
| Pins | 25 |
CAD (KiCad official)
- Symbol:
LM3549SQX - Footprint:
Package_DFN_QFN:QFN-24-1EP_4x4mm_P0.5mm_EP2.7x2.7mm - 3D model: WQFN-24-EP(4x4) (KiCad packages3D, STEP)
- 3D model files:
lm3549sqx-etched.step/lm3549sqx-etched.glbcarry the MPN laser-etched on the die in a toggleableAdom.LaserEtchgroup (Fusion-ready);lm3549sqx.step/lm3549sqx.glbare the bare package body.
Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- Datasheet: Texas Instruments datasheet (28 pp, sha256
912c4e49951a58aa, retrieved 2026-10-08, tier: lcsc) - Extractor: parts-factory
2.0.0/extract_pins 0.3, primaryclaude-haiku-5-5(text), consensusclaude-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).