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LM3940IT-3.3

Public Made by Adom

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Texas Instruments Linear Voltage Regulators (LDO), TO-220. Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.

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LM3940IT-3.3

Texas Instruments · Linear Voltage Regulators (LDO) · TO-220

LM3940IT-3.3 from Texas Instruments, in a TO-220. 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 IN power_in Input voltage supply (4.5 V to 5.5 V recommended); a 0.47-µF capacitor should be connected at this input.
2 GND power_in Common ground.
3 OUT power_out Regulated 3.3-V output, up to 1 A; a 33-µF low ESR capacitor should be connected to this pin.

Key specifications

Parameter Value
Manufacturer Texas Instruments
Package TO-220
Category Power Supply Chip
Pins 3

Electrical characteristics

Limits as printed in the datasheet (page.json metadata.characteristics carries them as data).

Parameter Symbol Min Typ Max Unit Conditions Page
Output voltage VOUT 3.2 3.3 3.4 V 5 mA ≤ IOUT ≤ 1 A, TJ = 25°C 5
Output voltage VOUT 3.13 3.47 V 5 mA ≤ IOUT ≤ 1 A, -40°C ≤ TJ ≤ 125°C 5
Line regulation 20 40 mV IOUT = 5 mA, 4.5 V ≤ VIN ≤ 5.5 V 5
Load regulation 35 50 mV 50 mA ≤ IOUT ≤ 1 A, TJ = 25°C 5
Load regulation 35 80 mV 50 mA ≤ IOUT ≤ 1 A, -40°C ≤ TJ ≤ 125°C 5
Quiescent current IQ 10 15 mA 4.5 V ≤ VIN ≤ 5.5 V, IOUT = 5 mA, TJ = 25°C 5
Quiescent current IQ 10 20 mA 4.5 V ≤ VIN ≤ 5.5 V, IOUT = 5 mA, -40°C ≤ TJ ≤ 125°C 5
Quiescent current IQ 110 200 mA VIN = 5 V, IOUT = 1 A, TJ = 25°C 5
Quiescent current IQ 110 250 mA VIN = 5 V, IOUT = 1 A, -40°C ≤ TJ ≤ 125°C 5
Dropout voltage VDO 0.5 0.8 V IOUT = 1 A, TJ = 25°C 5
Dropout voltage VDO 0.5 1 V IOUT = 1 A, -40°C ≤ TJ ≤ 125°C 5
Dropout voltage VDO 110 150 mV IOUT = 100 mA, TJ = 25°C 5
Dropout voltage VDO 110 200 mV IOUT = 100 mA, -40°C ≤ TJ ≤ 125°C 5
Short-circuit current IOUT(SC) 1.2 1.7 A RL = 0 5
Output impedance ZOUT 35 mΩ IOUT (DC) = 100 mA, IOUT (AC) = 20 mA (rms), ƒ = 120 Hz 5
Output noise voltage en 150 μV(rms) ƒBW = 10 Hz, 100 kHz, IOUT = 5 mA 5
Input supply voltage VIN -0.3 7.5 V 4
Storage temperature Tstg -65 150 °C 4
ESD HBM V(ESD) -2000 2000 V Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001 4
ESD CDM V(ESD) -500 500 V Charged-device model (CDM), per JEDEC specification JESD22-C101 4
Junction temperature TJ -40 125 °C 4
Input supply voltage VIN 4.5 5.5 V 4
Junction-to-ambient thermal resistance, High-K RθJA 23.3 °C/W TO-220 (NDE) 4
Junction-to-case (top) thermal resistance RθJC(top) 16.1 °C/W TO-220 (NDE) 4
Junction-to-board thermal resistance RθJB 4.8 °C/W TO-220 (NDE) 4
Junction-to-top characterization parameter ψJT 2.7 °C/W TO-220 (NDE) 4
Junction-to-board characterization parameter ψJB 4.8 °C/W TO-220 (NDE) 4
Junction-to-case (bottom) thermal resistance RθJC(bot) 1.1 °C/W TO-220 (NDE) 4

Materials and finish

As the datasheet states them (page.json metadata.appearance; the 3D model's colours follow it).

Part Material Colour / plating Datasheet says Page
contacts copper capacitor, and to the LDO ground pin as close to each other as possible, connected by a wide, component-side, copper surface. The use of vias and long traces to create LDO circuit connections is stron 11

CAD (KiCad official)

  • Symbol: LM3940IT-3.3
  • Footprint: Package_TO_SOT_THT:TO-220-3_Vertical
  • 3D model: TO-220 (KiCad packages3D, STEP)
  • 3D model files: lm3940it-3-3-etched.step / lm3940it-3-3-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); lm3940it-3-3.step / lm3940it-3-3.glb are the bare package body.

Provenance

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

  • Datasheet: Texas Instruments datasheet (28 pp, sha256 88a74e653c540072, retrieved 2026-10-23, tier: lcsc)
  • Extractor: parts-factory 2.0.0 / extract_pins 0.3, primary claude-sonnet-5-5 (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