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SN74HC245

Public Made by Adom

by adom

TI octal bus transceiver with 3-state outputs, SOIC-20. Direction + output-enable, 8 channels, 2-6 V. Datasheet-verified.

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Contents

README

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SN74HC245

Texas Instruments · Octal bus transceiver (3-state) · SOIC-20

An octal (8-bit) bus transceiver with 3-state outputs, in a SOIC-20, for driving data both ways between two buses. Eight channels connect the A bus to the B bus; a single DIR pin sets the direction (A to B when high, B to A when low) and an active-low output-enable (/OE) puts all outputs into high-impedance so several devices can share the bus. It buffers and level-isolates a microcontroller bus, drives long traces or backplanes, and protects weak drivers. Runs 2-6 V.

Pinout

Pin Name Type Function
1 DIR input Direction control input. When DIR is high, data flows from A bus to B bus; when low, data flows from B bus to A bus. CMOS logic input, held at VCC or GND per recommended operating conditions.
2 A1 bidirectional Channel 1 A-side data pin. Acts as input when DIR is high (transmits to B1) or output when DIR is low (driven by B1). High-impedance when OE is high.
3 A2 bidirectional Channel 2 A-side data pin. Bidirectional; direction set by DIR, enabled by OE (active-low).
4 A3 bidirectional Channel 3 A-side data pin. Bidirectional; direction set by DIR, enabled by OE (active-low).
5 A4 bidirectional Channel 4 A-side data pin. Bidirectional; direction set by DIR, enabled by OE (active-low).
6 A5 bidirectional Channel 5 A-side data pin. Bidirectional; direction set by DIR, enabled by OE (active-low).
7 A6 bidirectional Channel 6 A-side data pin. Bidirectional; direction set by DIR, enabled by OE (active-low).
8 A7 bidirectional Channel 7 A-side data pin. Bidirectional; direction set by DIR, enabled by OE (active-low).
9 A8 bidirectional Channel 8 A-side data pin. Bidirectional; direction set by DIR, enabled by OE (active-low).
10 GND power_in Ground reference (0 V). Return path for VCC supply current and signal reference.
11 B8 bidirectional Channel 8 B-side data pin. Bidirectional; paired with A8. Direction set by DIR, enabled by OE (active-low).
12 B7 bidirectional Channel 7 B-side data pin. Bidirectional; paired with A7. Direction set by DIR, enabled by OE (active-low).
13 B6 bidirectional Channel 6 B-side data pin. Bidirectional; paired with A6. Direction set by DIR, enabled by OE (active-low).
14 B5 bidirectional Channel 5 B-side data pin. Bidirectional; paired with A5. Direction set by DIR, enabled by OE (active-low).
15 B4 bidirectional Channel 4 B-side data pin. Bidirectional; paired with A4. Direction set by DIR, enabled by OE (active-low).
16 B3 bidirectional Channel 3 B-side data pin. Bidirectional; paired with A3. Direction set by DIR, enabled by OE (active-low).
17 B2 bidirectional Channel 2 B-side data pin. Bidirectional; paired with A2. Direction set by DIR, enabled by OE (active-low).
18 B1 bidirectional Channel 1 B-side data pin. Bidirectional; paired with A1. Direction set by DIR, enabled by OE (active-low).
19 OE input Active-low output enable. When OE is low, transceivers are enabled per DIR; when OE is high, all A and B pins are placed in high-impedance (isolation) state. Should be tied to VCC through a pullup resistor during power-up/down to guarantee high-Z.
20 VCC power_in Positive supply pin. Recommended operating range 2 V to 6 V (5 V nominal). Bypass with 0.1 uF ceramic capacitor to GND.

Key specifications

Parameter Value
Type Octal bus transceiver, 3-state
Channels 8 (A1-A8 <-> B1-B8)
Direction DIR pin (A->B high, B->A low)
Output enable /OE (active-low, Hi-Z)
Logic family HC (high-speed CMOS)
Supply voltage 2-6 V
Package SOIC-20
Body (L×W×H) 12.8 × 7.5 × 2.35 mm

Ordering variants

Same part, different packaging or reel option.

  • SN74HC245DW (SOIC-20, tube)
  • SN74HC245DWR (SOIC-20, tape & reel)

CAD (KiCad official)

  • Symbol: 74xx:74HC245
  • Footprint: Package_SO:SOIC-20W_7.5x12.8mm_P1.27mm
  • 3D model: SOIC-20W (KiCad packages3D)
  • 3D model files: sn74hc245-etched.step / sn74hc245-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); sn74hc245.step / sn74hc245.glb are the bare package body.

Provenance

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

  • Datasheet: Texas Instruments datasheet (35 pp, sha256 c78c3a1bb10a438d, 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