component

TMI3257I

Public Unreviewed

by Ray

TMI DC-DC Converters, SOT-563. Datasheet-verified pinout, KiCad symbol/footprint/3D.

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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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Contents

README

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TMI3257I

TMI · DC-DC Converters · SOT-563

TMI3257I from TMI, in a SOT-563. Pinout and pin descriptions extracted from the manufacturer datasheet by ds2sf; symbol, footprint, and 3D from KiCad-official CAD.

Pinout

Pin Name Type Function
1 IN power_in Power supply input pin. Accepts 4.5V to 18V (absolute max 20V). Bypass with a low-ESR ceramic capacitor (e.g. 22µF) close to the pin. Also feeds the internal LDO and high-side switch drain.
2 LX output Switching node output. Connects to the external inductor and the low side of the bootstrap capacitor. Absolute max -0.3V to 20V (transient -5V to 22V for <10ns).
3 GND power_in Device ground reference and low-side MOSFET source return. Tie to the system ground plane with a low-impedance connection.
4 BS passive Bootstrap capacitor pin for the floating high-side gate driver supply. A ~0.1µF capacitor must be connected between LX and BS. Absolute max BS voltage 23V.
5 EN input Enable input. Drive high (>~1.1V rising threshold, 100mV hysteresis) to enable the IC; drive low to enter micro-power shutdown. Do not leave EN floating. Absolute max 20V.
6 FB input Output voltage feedback input. Connect to the center of the external resistor divider from VOUT to GND; regulated to VREF = 0.807V typ. Absolute max -0.3V to 6V.

Key specifications

Parameter Value
Manufacturer TMI
Package SOT-563
Category PMIC
Pins 6

CAD (KiCad official)

  • Symbol: TMI3257I
  • Footprint: Package_TO_SOT_SMD:SOT-563
  • 3D model: SOT-563 (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File Size Use it when
tmi3257i.step 448 KB You want the bare part, or you mark your own boards.
tmi3257i-etched.step 1.5 MB You want the part with TMI3257I already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 326 faces against 54 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: TMI datasheet (15 pp, sha256 b71a605a61ddbb09, 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