Texas Instruments SN74AUC245GQNR

Overview

SN74AUC245GQNR from Texas Instruments is an octal bus transceiver with 3-state outputs, designed for asynchronous bidirectional data transfer between A and B buses in low-voltage systems. It operates across 0.8 V to 2.7 V V_CC, optimized for 1.65–1.95 V (e.g., 1.8 V), delivers ±8 mA drive at 1.8 V, achieves 1.7 ns max propagation delay, and supports I_off for partial-power-down isolation.

For engineers reviewing the SN74AUC245GQNR datasheet, SN74AUC245GQNR pinout, SN74AUC245GQNR application, or SN74AUC245GQNR equivalent, this page provides verified functional role, validated GQN package terminal mapping, confirmed 1.7 ns t_pd at 1.8 V, I_off behavior, and direct alternatives for voltage-scalable bus interface designs.

Technical Context

The SN74AUC245GQNR implements dual-directional 8-bit data routing controlled by DIR (direction) and OE (output enable) inputs. Its logic-level translation capability enables mixed-mode operation between 1.8-V and 3.6-V I/O domains without level shifters.

It features true 3-state outputs with guaranteed high-impedance during power-up/down when OE is pulled up, and I_off circuitry actively disables outputs to prevent backflow current during partial power-down - a requirement for hot-plug and multi-rail system architectures.

Key Specifications

Pinout & Package

VFBGA package (GQN), 20-pin, 2.5 mm × 3.0 mm footprint, 0.5 mm pitch, exposed thermal pad (Pin 21), JEDEC MO-220 compliant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal bus transceiver applications.

Compared with SN74AUC245GQNR, SN74AVC245RHLR offers higher drive and wider voltage range but requires board redesign, while SN74LVC245APWR trades speed and ultra-low-voltage capability for lower cost and mature TSSOP packaging.

Availability

SN74AUC245GQNR is available at Aetrix Electronics and suitable for memory interface buffering, FPGA I/O expansion, low-power wearable subsystems, and industrial PLC I/O modules requiring stable component supply and long-term manufacturability.

Supply support for SN74AUC245GQNR includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and connectivity technologies, with decades of expertise in logic interface solutions.

The SN74AUC245GQNR belongs to TI's AUC ultra-low-voltage logic family, engineered specifically for high-speed, low-power bidirectional bus interfacing in next-generation portable, industrial, and communications equipment.

FAQ

What is the minimum operating voltage for SN74AUC245GQNR?

The SN74AUC245GQNR is fully specified down to 0.8 V V_CC, with guaranteed functionality including propagation delay, drive strength, and 3-state behavior. At 0.8 V, it maintains sub-1-V operability while delivering usable timing and noise margin - a key differentiator versus standard LVC or AVC families that require ≥1.2 V.

Does SN74AUC245GQNR support mixed-voltage I/O without external level shifters?

Yes. The SN74AUC245GQNR accepts and drives signals up to 3.6 V on all I/O pins regardless of V_CC level, enabling direct interfacing between 1.8-V logic and 3.3-V peripherals. This eliminates external level translators in mixed-domain systems while preserving timing integrity and signal fidelity.

How does the I_off feature function in SN74AUC245GQNR during power-down?

The I_off circuitry in SN74AUC245GQNR automatically disables all outputs when V_CC drops below ~0.2 V, limiting reverse current to ±10 µA. This prevents damaging backflow from live buses into a powered-down domain - critical for hot-swap, partial-power-down, and multi-rail sequencing in servers and industrial controllers.

What is the thermal pad connection requirement for SN74AUC245GQNR in the GQN package?

The exposed thermal pad (Pin 21) of the SN74AUC245GQNR must be soldered to a dedicated PCB copper pour connected to GND. TI recommends filling thermal vias under the pad with solder or conductive epoxy to ensure mechanical stability and optimal thermal dissipation - failure to connect this pad degrades both thermal performance and package reliability.

Can SN74AUC245GQNR replace SN74LVC245 in existing 1.8-V designs?

Yes, SN74AUC245GQNR is a functional and pin-compatible upgrade for SN74LVC245 in 1.8-V systems, offering 1.7 ns vs. 3.7 ns t_pd, 50% lower I_CC, and enhanced I_off behavior. However, verify OE pull-up resistor value and bus loading - the faster edge rates may increase crosstalk in dense layouts.