Texas Instruments SN74AVC2T45DDFR

Overview

SN74AVC2T45DDFR from Texas Instruments is a 2-bit dual-supply bus transceiver enabling bidirectional voltage-level translation between 1.2V, 1.5V, 1.8V, 2.5V, and 3.3V domains. It features independent VCCA (1.2–3.6V) and VCCB (1.2–3.6V) rails, 4.6V I/O overvoltage tolerance, Ioff partial-power-down support, and VCC isolation. It serves as a core interface IC in multi-voltage SoC interconnects, such as between application processors and memory or peripheral buses in smartphones.

For engineers reviewing the SN74AVC2T45DDFR datasheet, SN74AVC2T45DDFR pinout, SN74AVC2T45DDFR application, or SN74AVC2T45DDFR equivalent, key selection criteria include verified dual-rail level-shifting capability across sub-1.8V nodes, DIR-controlled directionality without OE pin, guaranteed 240–500 Mbps data rate per voltage pair, thermal performance in SOT-23-8 package, and compatibility with NanoFree™ footprint constraints.

Technical Context

This device implements a non-inverting, asynchronous, dual-port transceiver architecture with separate A- and B-side I/O banks each referenced to their own supply rail. Direction control is implemented via a single DIR input referenced to VCCA, determining whether data flows A→B (DIR = HIGH) or B→A (DIR = LOW).

The internal circuitry includes VCC isolation logic that forces both ports into high-impedance when either VCCA or VCCB is at GND, and Ioff circuitry that limits off-state current to ±5 µA per port under partial-power-down conditions. Input thresholds scale with respective supply rails, supporting robust operation across mixed-voltage interfaces.

Key Specifications

Pinout & Package

SOT-23-8 (DDF) package: 2.90 mm × 1.60 mm × 1.10 mm body, 0.65 mm pitch, surface-mount, lead-free, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74AVCH2T45DDFR and TXS0102DCUR, SN74AVC2T45DDFR uniquely balances low quiescent current, VCC isolation, and full 500 Mbps capability - making it optimal for high-reliability, multi-rail SoC interconnects where deterministic direction control and fault containment are mandatory.

Availability

SN74AVC2T45DDFR is available at Aetrix Electronics and suitable for smartphone baseband interfaces, server BMC subsystems, and industrial sensor hubs requiring stable component supply, long-term lifecycle support, and RoHS-compliant SOT-23-8 packaging.

Supply support for SN74AVC2T45DDFR 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 company specializing in analog, embedded processing, and connectivity technologies, with leadership in precision analog and low-power interface solutions.

The SN74AVC2T45DDFR belongs to TI's AVC (Advanced Very-low-voltage CMOS) logic family, designed specifically for ultra-low-voltage bidirectional level shifting in battery-powered and thermally constrained portable electronics.

FAQ

What voltage ranges does the SN74AVC2T45DDFR support on its A and B ports?

The SN74AVC2T45DDFR supports independent supply voltages from 1.2V to 3.6V on both VCCA and VCCB rails. This enables translation between any combination of 1.2V, 1.5V, 1.8V, 2.5V, and 3.3V domains - for example, 1.2V↔3.3V or 1.8V↔2.5V - with guaranteed operation across the full industrial temperature range (–40°C to +85°C). The SN74AVC2T45DDFR does not support 5V supplies.

Does the SN74AVC2T45DDFR require external pull-up or pull-down resistors on unused I/O pins?

Yes. The SN74AVC2T45DDFR requires all unused data inputs (A1, A2, B1, B2) to be held at a valid logic HIGH or LOW level - either tied to VCCA/VCCB or GND - to prevent excess leakage current through the internal CMOS structure. Floating inputs are not permitted. DIR must also be actively driven (not left floating), typically via a pull-up to VCCA or direct connection to GND/VCCA depending on desired default direction.

How does the VCC isolation feature function in the SN74AVC2T45DDFR?

The VCC isolation feature in the SN74AVC2T45DDFR forces both A- and B-port I/Os into a high-impedance state whenever either VCCA or VCCB is driven to GND. This prevents false logic levels from propagating across the transceiver during power sequencing faults, brownouts, or hot-swap events. The behavior is hardware-enforced and requires no external circuitry - a key differentiator from alternatives like TXS0102DCUR which lack this protection.

What is the maximum data rate supported by the SN74AVC2T45DDFR, and under what conditions?

The SN74AVC2T45DDFR supports up to 500 Mbps when translating from 1.8V to 3.3V. Other validated rates include 320 Mbps (<1.8V ↔ 3.3V), 320 Mbps (↔ 2.5V or 1.8V), 280 Mbps (↔ 1.5V), and 240 Mbps (↔ 1.2V). These values are measured under specified load and transition conditions per TI's SCES531N datasheet and reflect guaranteed minimum timing margins - not theoretical limits.

Is the SN74AVC2T45DDFR pin-compatible with other members of the SN74AVC2T45 family?

Yes. The SN74AVC2T45DDFR (SOT-23-8) shares identical pinout and electrical functionality with SN74AVC2T45DCT (SSOP-8) and SN74AVC2T45DCU (VSSOP-8), differing only in package dimensions and thermal characteristics. All variants use the same logic diagram, pin numbering, and functional behavior - enabling drop-in replacement across form factors when board layout permits mechanical fit.