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Contents

README

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LM51551QDSSTQ1

Texas Instruments · DC-DC Converters · WSON-12-EP(2x3)

LM51551QDSSTQ1 from Texas Instruments, in a WSON-12-EP(2x3). 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 BIAS power_in VCC regulator power supply voltage input (3.5V to 45V); connect bypass capacitor between this pin and PGND.
2 VCC power_out Internal VCC regulator output and MOSFET driver power supply voltage (6.85V typical); connect ceramic bypass capacitor to PGND.
3 GATE output N-channel MOSFET gate drive output (1.5A peak); connect via short low-inductance path directly to MOSFET gate.
4 PGND power_in Power ground pin; connect via wide short low-inductance path to current sense resistor ground connection.
5 CS input Current sense input pin; connect via short path to positive side of current sense resistor (100mV ±7% threshold).
6 COMP output Internal transconductance error amplifier output; connect loop compensation network (RCOMP, CCOMP) between this pin and PGND.
7 AGND power_in Analog ground pin; connect via wide short path to analog ground plane layer.
8 FB input Error amplifier inverting input; connect voltage divider from output to set 1.0V ±1% target voltage in boost/SEPIC topologies.
9 SS input Soft-start time programming pin; external capacitor and internal 10µA current source set soft-start ramp rate, ground to AGND.
10 RT input Switching frequency setting pin; program switching frequency from 100kHz to 2.2MHz via resistor between RT and AGND.
11 PGOOD output Power good indicator open-drain output; pulls low when FB below 87-93% of VREF, pull up to system voltage (max 1mA sink).
12 UVLO/SYNC input Undervoltage lockout and external clock sync input; connect via resistor divider to set startup/shutdown thresholds or apply sync pulses.
13 EP passive Exposed pad (from the footprint; not named in the datasheet pin table).

Key specifications

Parameter Value
Manufacturer Texas Instruments
Package WSON-12-EP(2x3)
Category Power Management (PMIC)
Pins 13

CAD (KiCad official)

  • Symbol: LM51551QDSSTQ1
  • Footprint: Package_SON:WSON-12-1EP_3x2mm_P0.5mm_EP1x2.65
  • 3D model: WSON-12-EP(2x3), generated from the KiCad footprint (body from the F.Fab outline, terminals on the pads, 0.75 mm nominal WSON height). Neither the vendor nor KiCad ships a 3D model for this package, so the dimensions are nominal, not the manufacturer's CAD (STEP)
  • 3D model files: lm51551qdsstq1-etched.step / lm51551qdsstq1-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); lm51551qdsstq1.step / lm51551qdsstq1.glb are the bare package body.

Provenance

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

  • Datasheet: Texas Instruments datasheet (50 pp, sha256 a8503f9fa4bec785, retrieved 2026-10-01, tier: lcsc)
  • Datasheet language: Chinese. Pin names, descriptions, and specs on this page were extracted and translated to English by ds2sf; the linked PDF is the manufacturer original.
  • 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