Texas Instruments SN74AXCH2T45DCUR

Overview

SN74AXCH2T45 from Texas Instruments is a 2-bit non-inverting bus transceiver with dual configurable power rails (VCCA/VCCB), bus-hold inputs, and VCC isolation. It supports level-shifting between 0.65 V and 3.6 V on each port, operates from –40°C to +125°C, and delivers up to 380 Mbps data rate in 1.8 V → 3.3 V translation. It enables bidirectional voltage translation in mixed-supply SoC interconnects.

For engineers reviewing the SN74AXCH2T45 datasheet, SN74AXCH2T45 pinout, SN74AXCH2T45 application, or SN74AXCH2T45 equivalent, key selection criteria include its dual-rail flexibility, Ioff partial-power-down support, glitch-free supply sequencing, bus-hold circuitry on data I/Os (not DIR), and VCC isolation behavior below 100 mV.

Technical Context

The SN74AXCH2T45 implements asynchronous bidirectional data flow controlled by a single DIR input referenced to VCCA. Its dual-rail architecture allows independent operation of A-port (VCCA-tracked) and B-port (VCCB-tracked), enabling translation across wide voltage combinations including sub-1-V domains. The DIR control logic is strictly VCCA-referenced, decoupling direction control from B-port supply stability.

Bus-hold circuitry is embedded only on A1/A2/B1/B2 data I/Os-not on DIR or power pins-and remains active whenever its associated supply (VCCA or VCCB) is present, regardless of DIR state. VCC isolation forces both ports into high-impedance when either VCCA or VCCB drops below 100 mV, preventing back-drive during power sequencing.

Key Specifications

Pinout & Package

SN74AXCH2T45DCUR uses the 8-pin VSSOP (DCU) package with nominal body size 2.30 mm × 2.00 mm and 0.5-mm lead pitch. Thermal resistance RθJA = 242.9°C/W supports operation in compact, thermally constrained layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74AVCH2T45DCUR and SN74LXC2T45DCUR, the SN74AXCH2T45 uniquely combines bus-hold, VCC isolation, and full 0.65 V–3.6 V dual-rail compatibility - making it optimal for thermally constrained, mixed-voltage systems requiring autonomous fault containment and zero-external-component robustness.

Availability

SN74AXCH2T45DCUR is available at Aetrix Electronics and suitable for industrial sensor hubs, automotive body control modules, enterprise SSD controllers, and wireless baseband ASIC interconnects requiring stable component supply across extended temperature and mixed-voltage operating conditions.

Supply support for SN74AXCH2T45DCUR 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 automotive, industrial, and communications qualification expertise.

The SN74AXCH2T45 belongs to TI's AXCH family of advanced configurable level-shifters, designed specifically for low-voltage, high-reliability interconnect in next-generation mixed-domain systems where power sequencing autonomy and input robustness are critical.

FAQ

What is the minimum operating voltage for SN74AXCH2T45DCUR on each supply rail?

The SN74AXCH2T45DCUR supports VCCA and VCCB down to 0.65 V each, enabling direct interface with sub-1-V logic families such as ARM Cortex-M ultra-low-power cores and advanced-node FPGAs. Operation below 0.65 V is not characterized or guaranteed per the SCES881 datasheet.

Does SN74AXCH2T45DCUR require external pull-up or pull-down resistors on its data I/Os?

No. The SN74AXCH2T45DCUR integrates active bus-hold circuitry on A1, A2, B1, and B2 - automatically maintaining valid logic states on undriven or floating data lines. External resistors are explicitly discouraged in the datasheet and would interfere with bus-hold functionality.

How does the VCC isolation feature behave in SN74AXCH2T45DCUR during power-down sequences?

When either VCCA or VCCB falls below 100 mV, the SN74AXCH2T45DCUR disables all I/O outputs and forces them into high-impedance state - preventing back-current flow and protecting downstream devices. This occurs independently of DIR state or input voltage levels.

Is the DIR input of SN74AXCH2T45DCUR referenced to VCCA or VCCB?

The DIR input of SN74AXCH2T45DCUR is strictly referenced to VCCA, as confirmed in the "Description" and "Pin Functions" sections of the SCES881 datasheet. Its logic thresholds scale with VCCA, not VCCB - meaning DIR must be driven by a signal compliant with the A-port voltage domain.

What is the maximum propagation delay for SN74AXCH2T45DCUR under worst-case conditions?

The maximum propagation delay for SN74AXCH2T45DCUR is 177 ns, measured at VCCA = 0.7 V and VCCB = 0.7 V over –40°C to 125°C. At higher voltages (e.g., VCCA = 1.8 V, VCCB = 3.3 V), typical tpd drops to 5 ns, supporting high-speed interconnects.