component

LM1117-3.3

Public Unreviewed

by Ray

TI 800 mA low-dropout regulator, SOT-223. Fixed 3.3 V, 1.2 V dropout, current limit + thermal. Datasheet-verified.

componentvoltage-regulatorldo3v3sot-223texas-instruments
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README

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LM1117

Texas Instruments · 800 mA LDO regulator (fixed 3.3 V) · SOT-223

An 800 mA low-dropout linear regulator fixed at 3.3 V, in the SOT-223 tab package, TI's take on the ubiquitous 3.3 V rail supply. It regulates a higher input down to 3.3 V with about 1.2 V of dropout at full load, and includes current limiting and thermal shutdown. Like the AMS1117 it needs a 10 uF output capacitor (tantalum or ceramic) for stability, and the tab is the output and heat path. It also comes in adjustable and other fixed voltages; this page is the fixed 3.3 V. Pinout is GND, VOUT (tab), VIN.

Pinout

Pin Name Type Function
1 ADJ/GND input Adjust pin for the adjustable (LM1117-ADJ) option: connects to the top of an external resistor divider from VOUT to set VOUT = 1.25 V x (1 + R2/R1); adjust-pin current is 60 uA typical (120 uA max over temperature). For fixed-voltage options this pin is ground (0 V reference).
2 VOUT power_out Regulated output voltage pin, up to 800 mA of load current. Requires a minimum 10-uF tantalum capacitor to GND for output stability and transient response. Electrically the same net as pin 4 and the tab.
3 VIN power_in Unregulated input voltage pin, recommended operating range up to 15 V (absolute max 20 V to GND). Must be at least VOUT + 1.2 V (dropout at 800 mA) for the regulator to remain in regulation. Bypass with an input capacitor close to the pin.
4 VOUT power_out Regulated output voltage pin (same net as pin 2 and the SOT-223 tab). Included on the SOT-223 (DCY) package as a second output lead to help distribute the 800 mA output current.

Key specifications

Parameter Value
Type Fixed LDO linear regulator
Output voltage 3.3 V (fixed)
Output current 800 mA
Dropout 1.2 V max at 800 mA
Protection current limit + thermal shutdown
Output cap 10 µF (stability)
Pinout 1=GND, 2=VOUT (tab), 3=VIN
Package SOT-223

Ordering variants

Same part, different packaging or reel option.

  • LM1117MP-3.3 (SOT-223)
  • LM1117MPX-3.3 (SOT-223, tape & reel)

CAD (KiCad official)

  • Symbol: Regulator_Linear:LM1117DT-3.3
  • Footprint: Package_TO_SOT_SMD:SOT-223-3_TabPin2
  • 3D model: SOT-223 (KiCad packages3D)

Provenance

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

  • Datasheet: Texas Instruments datasheet (46 pp, sha256 35892f3a8673fae9, retrieved 2026-08-17, tier: manufacturer)
  • 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