Texas Instruments SN74AUCH245RGYR

Overview

SN74AUCH245RGYR from Texas Instruments is an octal bus transceiver optimized for 1.8-V operation with 3.6-V I/O tolerance, supporting mixed-mode signal interfacing between voltage domains. It features ±8-mA output drive at 1.8 V, 2 ns max propagation delay, sub-1-V operability (down to 0.8 V), and integrated bus-hold circuitry eliminating external pull resistors.

For engineers reviewing the SN74AUCH245RGYR datasheet, SN74AUCH245RGYR pinout, SN74AUCH245RGYR application, or SN74AUCH245RGYR equivalent, key selection criteria include Ioff-enabled partial-power-down support, 20-µA max ICC low-power operation, and QFN-20 (RGY) package compatibility with high-density PCB layouts.

Technical Context

The SN74AUCH245RGYR implements asynchronous bidirectional data transfer between A and B buses via DIR-controlled direction and OE-gated 3-state outputs. Its Ioff circuitry actively disables outputs during power-down to prevent backflow current, meeting JESD 78 Class II latch-up requirements (>100 mA).

Bus-hold inputs maintain valid logic states on undriven lines without external components, while ESD protection exceeds JESD 22 standards: 2000-V HBM, 200-V MM, and 1000-V CDM. The device operates across 0.8 V–2.7 V VCC but is specifically characterized for 1.65 V–1.95 V nominal use.

Key Specifications

Pinout & Package

VQFN-20 (RGY) package: 3.5 mm × 4.5 mm, 0.5 mm pitch, 1 mm max height, exposed thermal pad for enhanced thermal dissipation and mechanical stability.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74AUCH245RGYR, SN74AVCH245RHLR offers greater drive strength but sacrifices bus-hold integration, while SN74LVC245APWR lacks Ioff, bus-hold, and sub-1-V operation-making SN74AUCH245RGYR uniquely suited for compact, multi-rail, ultra-low-power embedded interfaces.

Availability

SN74AUCH245RGYR is available at Aetrix Electronics and suitable for mobile baseband interfaces, low-power FPGA I/O bridging, and industrial PLC backplanes requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for SN74AUCH245RGYR 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 delivering analog, embedded processing, and connectivity solutions for industrial, automotive, and personal electronics markets.

The SN74AUCH245RGYR belongs to TI's advanced low-voltage logic family, engineered specifically for mixed-signal voltage-domain bridging in space-constrained, power-sensitive portable and embedded systems.

FAQ

What is the minimum operating voltage for the SN74AUCH245RGYR?

The SN74AUCH245RGYR supports operation down to 0.8 V VCC, with full functionality specified across 0.8 V–2.7 V. It is optimized for 1.65 V–1.95 V operation, where parameters like ±8-mA output drive and 2 ns max tpd are guaranteed. Operation below 0.8 V is not characterized and may result in undefined behavior or failure to meet timing or drive specifications.

Does the SN74AUCH245RGYR require external pullup resistors on its data inputs?

No, the SN74AUCH245RGYR does not require external pullup or pulldown resistors on its data inputs because it integrates active bus-hold circuitry on all A and B port pins. This feature maintains valid logic states on undriven or floating inputs, reducing BOM count and PCB area. Using external resistors with enabled bus-hold is explicitly discouraged in the datasheet.

How does the Ioff feature of the SN74AUCH245RGYR protect the system during partial power-down?

The Ioff feature in the SN74AUCH245RGYR disables all outputs when VCC is removed or near zero, preventing current backflow from live I/O lines into the unpowered device. This protects both the SN74AUCH245RGYR and connected components from damage during hot-swap or staggered power sequencing-critical in modular systems like PLC backplanes or multi-board wearables.

What is the thermal pad requirement for the RGY package of the SN74AUCH245RGYR?

The RGY package of the SN74AUCH245RGYR includes an exposed thermal pad that must be soldered to the PCB for reliable thermal dissipation and mechanical integrity. TI recommends connecting the pad to a solid ground plane using multiple thermal vias. Failure to solder the pad may cause excessive junction temperature rise, reduced reliability, and potential solder joint fatigue during thermal cycling.

Can the SN74AUCH245RGYR interface between a 1.8-V microcontroller and a 3.3-V peripheral?

Yes, the SN74AUCH245RGYR supports this exact use case: its I/O pins are tolerant up to 3.6 V regardless of VCC, allowing safe connection to 3.3-V peripherals while powered from a 1.8-V supply. The device maintains full logic-level compatibility, 2 ns propagation delay, and ±8-mA drive strength-enabling direct, robust, and low-latency bridging without external level-shifting components.