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Contents

README

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LM51581QRTERQ1

Texas Instruments · DC-DC Converters · WQFN-16(3x3)

LM51581QRTERQ1 from Texas Instruments, in a WQFN-16(3x3). 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 PGND power_in Power ground pin; source connection of the internal N-channel power MOSFET.
2 VCC power_out Output of the internal VCC regulator and supply voltage input of the internal MOSFET driver; connect 1-µF ceramic bypass capacitor from this pin to PGND.
3 BIAS power_in Supply voltage input to the VCC regulator; operating range 3.2V to 60V absolute maximum 65V; connect bypass capacitor from this pin to PGND.
4 PGOOD tri_state Power-good indicator; open-drain output which goes low if FB is below the undervoltage threshold (VUVTH); connect pullup resistor to system voltage rail.
5 RT input Switching frequency setting pin; switching frequency is programmed by a single resistor between RT and AGND in the range 100 kHz to 2.2 MHz.
6 EN/UVLO/SYNC input Enable/UVLO/synchronization pin; enables converter (>VEN threshold), programs undervoltage lockout via resistive voltage divider, and accepts external negative pulse for clock synchronization.
7 AGND power_in Analog ground pin; connect to the analog ground plane through a wide and short path.
8 COMP output Output of the internal transconductance error amplifier; connect loop compensation components between this pin and AGND.
9 FB input Inverting input of the error amplifier; connect voltage divider to set output voltage in boost, SEPIC, or primary-side regulated flyback topologies; input range 0V to 4.0V.
10 SS input Soft-start time programming pin; external capacitor and internal current source set the ramp rate of the internal error amplifier reference during soft start.
11 MODE input Mode configuration pin; setting controls hiccup mode protection and spread spectrum features via voltage level (0V, 370mV, 620mV, or >1V) or resistor to AGND.
12 NC unconnected No internal electrical contact.
13 SW output Switch pin; drain connection of the internal N-channel power MOSFET; 85V absolute maximum rating, 5-ns transient minimum -6V.
14 SW output Switch pin; drain connection of the internal N-channel power MOSFET; 85V absolute maximum rating, 5-ns transient minimum -6V.
15 NC unconnected No internal electrical contact.
16 PGND power_in Power ground pin; source connection of the internal N-channel power MOSFET.
17 EP passive Exposed pad (from the footprint; not named in the datasheet pin table).

Key specifications

Parameter Value
Manufacturer Texas Instruments
Package WQFN-16(3x3)
Category Power Management (PMIC)
Pins 17

CAD (KiCad official)

  • Symbol: LM51581QRTERQ1
  • Footprint: Package_DFN_QFN:QFN-16-1EP_3x3mm_P0.5mm_EP1.7x1.7mm
  • 3D model: WQFN-16(3x3) (KiCad packages3D, STEP)
  • 3D model files: lm51581qrterq1-etched.step / lm51581qrterq1-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); lm51581qrterq1.step / lm51581qrterq1.glb are the bare package body.

Provenance

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

  • Datasheet: Texas Instruments datasheet (45 pp, sha256 c10929600ea42a9c, retrieved 2026-10-03, 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