component

SN74HC148

Public Made by Adom

by adom

TI 8-to-3 line priority encoder, SOIC-16. Encodes highest active input to 3-bit binary, cascadable. HC 2-6 V. Datasheet-verified.

componentlogicencoderpriority-encoder74hcsoic-16texas-instruments
Overview Files Discover Packages Releases Dependencies Issues Breadcrumbs Pull Requests Activity

3D Model

Open in new tab ↗
Loads on click. Unloads only if this page sits in the background.

Symbol & Footprint

Schematic Symbol

Open full view ↗
Loads on click. Unloads only if this page sits in the background.

PCB Footprint

Open full view ↗
Loads on click. Unloads only if this page sits in the background.

Datasheet

Open in new tab ↗
Loads on click. Unloads only if this page sits in the background.
Download PDF
Contents

README

markdown

SN74HC148

Texas Instruments · 8-to-3 priority encoder · SOIC-16

An 8-to-3 line priority encoder in high-speed CMOS, SOIC-16, the inverse of a decoder. It takes eight active-low inputs and outputs the 3-bit binary number of the highest-numbered one that is active, ignoring lower ones (the priority part). That turns a bank of buttons, interrupt lines, or switches into a compact binary code a microcontroller can read on three pins. Enable-in (EI), enable-out (EO), and group-select (GS) let you cascade two devices into a 16-to-4 encoder. Runs 2-6 V. The KiCad 74LS148 symbol shipped here is pin-identical.

Pinout

Pin Name Type Function
1 4 input Active-low data input 4. Requests encoding of octal value 4 when asserted (LOW).
2 5 input Active-low data input 5. Requests encoding of octal value 5 when asserted (LOW).
3 6 input Active-low data input 6. Requests encoding of octal value 6 when asserted (LOW).
4 7 input Active-low data input 7 (highest priority). Requests encoding of octal value 7 when asserted (LOW).
5 EI input Active-low enable input. All outputs are forced to their inactive (HIGH) state when EI is HIGH; encoding is enabled when EI is LOW. Used for cascading multiple stages.
6 A2 output Active-low encoded output bit 2 (MSB of the 3-bit octal code). Drives ±4 mA at Vcc = 5 V.
7 A1 output Active-low encoded output bit 1. Drives ±4 mA at Vcc = 5 V.
8 GND power_in Ground reference (0 V).
9 A0 output Active-low encoded output bit 0 (LSB of the 3-bit octal code). Drives ±4 mA at Vcc = 5 V.
10 0 input Active-low data input 0 (lowest priority). Requests encoding of octal value 0 when asserted (LOW) and no higher-numbered input is active.
11 1 input Active-low data input 1. Requests encoding of octal value 1 when asserted (LOW).
12 2 input Active-low data input 2. Requests encoding of octal value 2 when asserted (LOW).
13 3 input Active-low data input 3. Requests encoding of octal value 3 when asserted (LOW).
14 GS output Active-low group-select output. Goes LOW whenever any data input (0-7) is active and EI is LOW, indicating that a valid encoded value is present on A0-A2.
15 EO output Active-low enable output. Goes LOW when EI is LOW and no data input is asserted, signaling downstream cascaded encoders that they may drive the outputs.
16 VCC power_in Positive supply, 2 V to 6 V (5 V nominal). Icc max 80 µA.

Key specifications

Parameter Value
Type 8-to-3 priority encoder
Inputs 8 active-low (0-7)
Outputs 3-bit binary (A0-A2, active-low)
Priority highest active input wins
Cascade EI / EO / GS pins
Logic family HC (high-speed CMOS)
Supply voltage 2-6 V
Package SOIC-16

Ordering variants

Same part, different packaging or reel option.

  • SN74HC148D (SOIC-16, tube)
  • SN74HC148DR (SOIC-16, tape & reel)

CAD (KiCad official)

  • Symbol: 74xx:74LS148 (pin-compatible with 74HC148)
  • Footprint: Package_SO:SOIC-16_3.9x9.9mm_P1.27mm
  • 3D model: SOIC-16 (KiCad packages3D)
  • 3D model files: sn74hc148-etched.step / sn74hc148-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); sn74hc148.step / sn74hc148.glb are the bare package body.

Provenance

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

  • Datasheet: Texas Instruments datasheet (25 pp, sha256 ca65b15c3841afab, 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