Texas Instruments SN74AXCH1T45DRYR

Overview

SN74AXCH1T45 from Texas Instruments is a single-bit dual-supply bus transceiver enabling bidirectional voltage-level translation between 0.65 V and 3.6 V rails, featuring tri-state outputs, bus-hold inputs, and VCC isolation. It supports up to 500-Mbps data rates (1.8 V → 3.3 V), operates from –40°C to +125°C, and draws ≤16 µA combined supply current at 125°C. It is used in low-power I/O bridging between mixed-voltage SoCs and peripherals in portable electronics.

For engineers reviewing the SN74AXCH1T45 datasheet, SN74AXCH1T45 pinout, SN74AXCH1T45 application, or SN74AXCH1T45 equivalent, key selection criteria include configurable dual-rail operation, bus-hold elimination of external resistors, glitch-free power sequencing, Ioff partial-power-down support, and SON-6 package thermal performance for space-constrained PCBs.

Technical Context

The SN74AXCH1T45 implements a noninverting bidirectional translation architecture with independent VCCA and VCCB supplies, each supporting 0.65 V–3.6 V. Direction control is managed by the DIR pin referenced to VCCA, with logic thresholds scaling dynamically with VCCA voltage.

Its bus-hold circuitry actively maintains valid logic states on undriven A or B inputs without external biasing, and the VCC isolation feature forces both ports into high-impedance when either VCCA or VCCB falls below 100 mV - critical for robust system power sequencing in multi-rail environments.

Key Specifications

Pinout & Package

SN74AXCH1T45DRY uses a 6-pin SON (Small Outline No-Lead) package measuring 1.40 mm × 1.00 mm with wettable flanks, optimized for automated optical inspection and thermal dissipation in dense layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74AVCH1T45DRYR and TXS0101DCKR, the SN74AXCH1T45DRYR uniquely combines VCC isolation, bus-hold, and full 0.65–3.6-V dual-rail flexibility in a 1.4×1.0-mm SON package - making it the only option for robust, resistorless, mixed-voltage I/O bridging in thermally constrained, safety-critical, or hot-pluggable designs.

Availability

SN74AXCH1T45DRYR is available at Aetrix Electronics and suitable for mobile device I/O expansion, automotive body control modules, and industrial PLC digital I/O requiring stable component supply across extended temperature and mixed-voltage environments.

Supply support for SN74AXCH1T45DRYR 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 SN74AXCH1T45 belongs to TI's AXCH family of advanced configurable voltage translators, designed specifically for ultra-low-power, mixed-voltage system interconnect in space- and energy-constrained applications.

FAQ

What is the maximum supported data rate for SN74AXCH1T45DRYR?

The SN74AXCH1T45DRYR supports up to 500 Mbps when translating from 1.8 V to 3.3 V under specified conditions. This value is measured with defined load capacitance and temperature; actual achievable rate depends on PCB layout, signal integrity, and supply stability. The device does not guarantee 500 Mbps across all voltage combinations - e.g., 0.65 V ↔ 3.3 V operation yields slower timing due to reduced drive strength.

Does SN74AXCH1T45DRYR require external pullup or pulldown resistors?

No, the SN74AXCH1T45DRYR integrates active bus-hold circuitry on both A and B inputs, eliminating the need for external pullup or pulldown resistors. This feature maintains valid logic states on undriven or floating inputs, reducing BOM cost and PCB area. Using external resistors with enabled bus-hold is not recommended and may cause contention or increased power draw.

How does the VCC isolation feature work in SN74AXCH1T45DRYR?

In the SN74AXCH1T45DRYR, VCC isolation disables all I/O outputs and forces them into high-impedance when either VCCA or VCCB drops below 100 mV. This prevents back-driving or contention during asymmetric power-down sequences - for example, if VCCA remains active while VCCB is removed, both A and B ports go Hi-Z. The feature operates independently of DIR state and requires no external control.

Can SN74AXCH1T45DRYR operate with only one supply voltage?

Yes, the SN74AXCH1T45DRYR supports single-supply operation: tie VCCA and VCCB together to a common rail between 0.65 V and 3.6 V. In this mode, it functions as a standard noninverting buffer with tri-state control and bus-hold. DIR still controls direction, and all specifications - including Ioff and VCC isolation - remain valid, though isolation triggers only if that shared supply falls below 100 mV.

What is the thermal resistance (RθJA) of the SN74AXCH1T45DRYR package?

For the SN74AXCH1T45DRYR's 6-pin SON package (1.40 mm × 1.00 mm), the junction-to-ambient thermal resistance (RθJA) is 308.3°C/W under standard JEDEC test conditions. This value assumes a 2-layer board with 1-in² copper pad; actual thermal performance improves significantly with internal ground/power planes and thermal vias. RθJB (junction-to-board) is 181.7°C/W, indicating strong conduction path to the PCB.