Texas Instruments SN74AXCH2T45DTMR

Overview

SN74AXCH2T45DTMR from Texas Instruments is a 2-bit non-inverting bus transceiver with dual configurable power rails (VCCA/VCCB), bus-hold inputs, VCC isolation, and Ioff support. It operates from 0.65 V to 3.6 V per rail, supports –40°C to +125°C, delivers up to 380 Mbps (1.8 V → 3.3 V), and enables bidirectional level-shifting in mixed-voltage systems such as FPGA-to-ASIC interconnects.

For engineers reviewing the SN74AXCH2T45DTMR datasheet, SN74AXCH2T45DTMR pinout, SN74AXCH2T45DTMR application, or SN74AXCH2T45DTMR equivalent, key selection criteria include dual-rail voltage flexibility, bus-hold functionality on data I/Os only, glitch-free power sequencing, VCC isolation behavior, and X2SON-8 package thermal performance (RθJA = 225.9°C/W).

Technical Context

The SN74AXCH2T45DTMR implements asynchronous bidirectional data flow controlled by a single DIR input referenced to VCCA. Its fully independent A- and B-port power domains allow simultaneous operation at different voltages (e.g., 1.2 V ↔ 3.3 V), with propagation delay as low as 4 ns (A→B, VCCA=3.3 V, VCCB=3.3 V, TA=85°C) and disable time as low as 10 ns.

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

Key Specifications

Pinout & Package

X2SON-8 package (1.35 mm × 0.80 mm, 0.35 mm height), wettable flank terminals, no exposed pad.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74AVCH2T45DTMR and TXS0202DCUR, the SN74AXCH2T45DTMR uniquely balances high-speed bidirectional translation (380 Mbps), explicit DIR control for deterministic timing, and robust 125°C operation - making it optimal for mixed-voltage embedded systems requiring precise enable/disable sequencing and wide thermal margin.

Availability

SN74AXCH2T45DTMR is available at Aetrix Electronics and suitable for industrial automation, automotive body electronics, and enterprise storage applications requiring stable component supply, long lifecycle support, and guaranteed traceability.

Supply support for SN74AXCH2T45DTMR 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 over 90 years of innovation in power management and signal chain solutions.

The SN74AXCH2T45DTMR belongs to TI's AXCH advanced bus transceiver family, designed specifically for high-reliability, multi-voltage system interfacing in automotive, industrial, and communications infrastructure where robustness, thermal resilience, and precise level-shifting are critical.

FAQ

What is the minimum operating voltage for SN74AXCH2T45DTMR on each rail?

The SN74AXCH2T45DTMR supports VCCA and VCCB down to 0.65 V independently. At 0.65 V, it maintains functional bus-hold, Ioff, and VCC isolation features, though maximum data rate is reduced. Electrical characteristics are fully specified from 0.65 V, validated per TI SCES881 datasheet Section 6.3.

Does SN74AXCH2T45DTMR require external pull-up or pull-down resistors on its I/O pins?

No. The SN74AXCH2T45DTMR integrates bus-hold circuitry on all data I/O pins (A1, A2, B1, B2), actively holding undriven inputs at valid logic levels. TI explicitly states that external pull resistors are not recommended and may degrade performance or cause contention.

How does the VCC isolation feature behave in SN74AXCH2T45DTMR during power sequencing?

When either VCCA or VCCB falls below 100 mV, the SN74AXCH2T45DTMR automatically places both A- and B-port outputs into high-impedance state - regardless of DIR state or input voltage. This prevents back-driving, bus contention, or unintended current paths during asymmetric power-up/down sequences.

Can SN74AXCH2T45DTMR operate with VCCA = 1.8 V and VCCB = 2.5 V simultaneously?

Yes. The SN74AXCH2T45DTMR is explicitly designed for independent dual-rail operation. With VCCA = 1.8 V and VCCB = 2.5 V, it achieves A→B propagation delay of ≤7 ns and B→A delay of ≤6 ns (TA = 85°C), supporting reliable high-speed communication between heterogeneous logic domains.

What is the thermal performance of SN74AXCH2T45DTMR in its X2SON-8 package?

The SN74AXCH2T45DTMR in X2SON-8 has RθJA = 225.9°C/W (JEDEC JESD51-7, 2s2p test board). At 10 mA total I/O current and 3.3 V supplies, typical power dissipation is <1.5 mW, resulting in <0.35°C junction rise above ambient - enabling dense placement in thermally constrained IoT and automotive modules.