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Contents

README

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SN74LS138DR

Texas Instruments · Signal Switches, Multiplexers, Decoders · SOIC-16

SN74LS138DR from Texas Instruments, in a SOIC-16. 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 A input Binary select input A, one of three address inputs used with B and C to select which of the eight outputs is active when the device is enabled.
2 B input Binary select input B, one of three address inputs used with A and C to select which of the eight outputs is active when the device is enabled.
3 C input Binary select input C, one of three address inputs used with A and B to select which of the eight outputs is active when the device is enabled.
4 G2A input Active-low enable input; must be low, together with G2B low and G1 high, for the decoder outputs to be active (per function table).
5 G2B input Active-low enable input; must be low, together with G2A low and G1 high, for the decoder outputs to be active (per function table).
6 G1 input Active-high enable input; must be high, together with G2A and G2B both low, for the decoder outputs to be active (per function table).
7 Y7 output Active-low decoded output 7; driven low only when this output is selected and the device is enabled, otherwise held high.
8 GND power_in Ground reference for the device.
9 Y6 output Active-low decoded output 6; driven low only when this output is selected and the device is enabled, otherwise held high.
10 Y5 output Active-low decoded output 5; driven low only when this output is selected and the device is enabled, otherwise held high.
11 Y4 output Active-low decoded output 4; driven low only when this output is selected and the device is enabled, otherwise held high.
12 Y3 output Active-low decoded output 3; driven low only when this output is selected and the device is enabled, otherwise held high.
13 Y2 output Active-low decoded output 2; driven low only when this output is selected and the device is enabled, otherwise held high.
14 Y1 output Active-low decoded output 1; driven low only when this output is selected and the device is enabled, otherwise held high.
15 Y0 output Active-low decoded output 0; driven low only when this output is selected and the device is enabled, otherwise held high.
16 VCC power_in Positive supply voltage pin for the device.

Key specifications

Parameter Value
Manufacturer Texas Instruments
Package SOIC-16
Category Logic
Pins 16

CAD (KiCad official)

  • Symbol: SN74LS138DR
  • Footprint: Package_SO:SOIC-16_3.9x9.9mm_P1.27mm
  • 3D model: SOIC-16 (KiCad packages3D, STEP)
  • 3D model files: sn74ls138dr-etched.step / sn74ls138dr-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); sn74ls138dr.step / sn74ls138dr.glb are the bare package body.

Provenance

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

  • Datasheet: Texas Instruments datasheet (26 pp, sha256 4fd09e5dfa700e29, retrieved 2026-09-23, tier: manufacturer)
  • Extractor: parts-factory 2.0.0 / extract_pins 0.2, primary claude-sonnet-5 (vision), consensus claude-opus-4-8 (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