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

README

markdown

SN74LVC245

Texas Instruments · Bus transceiver / level translator · TSSOP-20

Eight-bit bidirectional bus transceiver that moves a byte between two buses under a single direction pin (DIR), with a 3-state output-enable (OE) to park the bus. Running from 1.65 to 3.6 V with 5 V-tolerant inputs, it doubles as a one-way level translator from 5 V logic down to 3.3 V, a common use on mixed-voltage boards. The outputs drive real bus loads at speed. A standard octal buffer/translator for parallel buses and port expansion.

Pinout

Pin Name Type Function
1 DIR input Direction control. When high, signal propagates from A to B; when low, signal propagates from B to A. CMOS input with VIH ≈ 0.65·VCC / VIL ≈ 0.35·VCC.
2 A1 bidirectional Transceiver I/O pin, port A channel 1. Driven when DIR=L and /OE=L; receives when DIR=H. Hi-Z when /OE=H. IOL/IOH up to 24 mA at VCC=3 V.
3 A2 bidirectional Transceiver I/O pin, port A channel 2. Driven when DIR=L and /OE=L; receives when DIR=H.
4 A3 bidirectional Transceiver I/O pin, port A channel 3. Driven when DIR=L and /OE=L; receives when DIR=H.
5 A4 bidirectional Transceiver I/O pin, port A channel 4. Driven when DIR=L and /OE=L; receives when DIR=H.
6 A5 bidirectional Transceiver I/O pin, port A channel 5. Driven when DIR=L and /OE=L; receives when DIR=H.
7 A6 bidirectional Transceiver I/O pin, port A channel 6. Driven when DIR=L and /OE=L; receives when DIR=H.
8 A7 bidirectional Transceiver I/O pin, port A channel 7. Driven when DIR=L and /OE=L; receives when DIR=H.
9 A8 bidirectional Transceiver I/O pin, port A channel 8. Driven when DIR=L and /OE=L; receives when DIR=H.
10 GND power_in Ground reference (0 V) for all internal logic and I/O.
11 B8 bidirectional Transceiver I/O pin, port B channel 8. Driven when DIR=H and /OE=L; receives when DIR=L.
12 B7 bidirectional Transceiver I/O pin, port B channel 7. Driven when DIR=H and /OE=L; receives when DIR=L.
13 B6 bidirectional Transceiver I/O pin, port B channel 6. Driven when DIR=H and /OE=L; receives when DIR=L.
14 B5 bidirectional Transceiver I/O pin, port B channel 5. Driven when DIR=H and /OE=L; receives when DIR=L.
15 B4 bidirectional Transceiver I/O pin, port B channel 4. Driven when DIR=H and /OE=L; receives when DIR=L.
16 B3 bidirectional Transceiver I/O pin, port B channel 3. Driven when DIR=H and /OE=L; receives when DIR=L.
17 B2 bidirectional Transceiver I/O pin, port B channel 2. Driven when DIR=H and /OE=L; receives when DIR=L.
18 B1 bidirectional Transceiver I/O pin, port B channel 1. Driven when DIR=H and /OE=L; receives when DIR=L.
19 ~{OE} input Active-low output enable. When low, the selected direction drivers are active; when high, both A and B port outputs are placed in high-impedance (Hi-Z).
20 VCC power_in Positive supply. Recommended operating range 1.65 V to 3.6 V. Inputs are 5.5 V-tolerant regardless of VCC. Decouple with 0.1 µF close to the pin.

Key specifications

Parameter Value
Type Octal bus transceiver (3-state)
Bits 8, bidirectional
Direction DIR pin
Output enable OE (active low)
Supply 1.65-3.6 V
Input tolerance 5 V-tolerant
Package TSSOP-20

Ordering variants

Same part, different packaging or reel option.

  • SN74LVC245APWR (TSSOP-20)
  • SN74LVC245ADWR (SOIC-20)
  • SN74LVC245ARGYR (VQFN-20)

CAD (KiCad official)

  • Symbol: Logic_LevelTranslator:SN74LVC245APW (KiCad official)
  • Footprint: Package_SO:TSSOP-20_4.4x6.5mm_P0.65mm
  • 3D model: TSSOP-20 (KiCad packages3D, STEP)
  • 3D model files: sn74lvc245-etched.step / sn74lvc245-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); sn74lvc245.step / sn74lvc245.glb are the bare package body.

Provenance

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

  • Datasheet: Texas Instruments datasheet (35 pp, sha256 f8c28b30ab2bf1a0, 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