Texas Instruments SN74LVC2T45DCTRE4

Overview

SN74LVC2T45 from Texas Instruments is a dual-bit, dual-supply noninverting bus transceiver enabling bidirectional voltage translation between 1.65 V and 5.5 V rails (e.g., 1.8 V ↔ 3.3 V, 3.3 V ↔ 5 V). It features configurable direction control (DIR referenced to VCCA), ±24-mA output drive at 3.3 V, 4-μA max ICC, and Ioff support for partial-power-down operation. It is used in mixed-voltage interconnects between microcontrollers and peripherals.

For engineers reviewing the SN74LVC2T45 datasheet, SN74LVC2T45 pinout, SN74LVC2T45 application, or SN74LVC2T45 equivalent, key selection criteria include dual-rail supply flexibility (VCCA/VCCB independent), high-speed translation up to 420 Mbps (3.3 V → 5 V), VCC isolation behavior, and NanoFree™ DCT package compatibility with space-constrained PCB layouts.

Technical Context

The SN74LVC2T45 implements asynchronous bidirectional data flow controlled by a single DIR input referenced to VCCA. Each port (A1/A2 and B1/B2) operates independently under its own supply rail - A port tracks VCCA (1.65–5.5 V), B port tracks VCCB (1.65–5.5 V) - enabling universal level translation across 1.8 V, 2.5 V, 3.3 V, and 5 V domains.

VCC isolation ensures both ports enter high-impedance state if either VCCA or VCCB = GND. Ioff circuitry disables outputs during power-down, limiting leakage to ±2 µA per pin and preventing backflow current. Propagation delays range from 0.5 ns (5 V → 5 V) to 17.7 ns (1.8 V → 1.8 V), with enable/disable times as low as 1.4 ns.

Key Specifications

Pinout & Package

The SN74LVC2T45 is packaged in an 8-pin SM8 (DCT) package measuring 2.95 mm × 4 mm, part of Texas Instruments' NanoFree™ wafer-chip-scale family. This leadless, near-chip-scale design minimizes PCB footprint and parasitic inductance for high-frequency signal integrity.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TXB0102RGTR and SN74AVC2T244RSWR, the SN74LVC2T45 uniquely combines explicit DIR control, full 1.65–5.5 V dual-rail operation, ±24-mA drive, and Ioff-enabled partial-power-down - making it the only option among the three qualified for mixed-voltage, high-speed, safety-critical interconnects.

Availability

SN74LVC2T45 is available at Aetrix Electronics and suitable for industrial sensor hubs, automotive infotainment links, enterprise SSD controllers, and telecom baseband FPGA bridges requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for SN74LVC2T45 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 and embedded processing technologies, with leadership in precision analog, power management, and interface solutions.

The SN74LVC2T45 belongs to TI's LVC logic family, designed specifically for low-voltage, mixed-rail digital interfacing in space- and power-constrained embedded systems across industrial, automotive, and communications markets.

FAQ

What is the maximum data rate supported by the SN74LVC2T45 in 3.3-V-to-5-V translation?

The SN74LVC2T45 supports up to 420 Mbps when translating signals from a 3.3-V domain to a 5-V domain, as specified in the switching characteristics table under VCCA = 3.3 V and VCCB = 5 V conditions. This performance enables use in high-speed SPI, parallel GPIO, and control-bus applications without added timing margin overhead. The SN74LVC2T45 achieves this using optimized CMOS output stages and low-propagation-delay internal logic.

How does the VCC isolation feature function in the SN74LVC2T45?

The VCC isolation feature in the SN74LVC2T45 forces both A and B ports into a high-impedance state whenever either VCCA or VCCB is at GND, regardless of the other rail's voltage. This prevents bus contention and backdrive current during asymmetric power sequencing - a critical safeguard in multi-rail systems such as automotive ECUs or telecom line cards. The SN74LVC2T45 implements this via internal detection circuitry tied to each supply pin.

Can the SN74LVC2T45 operate with VCCA = 1.8 V and VCCB = 2.5 V simultaneously?

Yes, the SN74LVC2T45 is fully specified to operate with VCCA = 1.8 V and VCCB = 2.5 V concurrently. Its dual-rail architecture allows independent supply voltages within the 1.65–5.5 V range on each port. In this configuration, A-side inputs/outputs swing between 0 V and 1.8 V, B-side between 0 V and 2.5 V, and DIR remains referenced to VCCA. The SN74LVC2T45 maintains valid logic thresholds and ≤17.7 ns propagation delay under these conditions.

What is the purpose of the Ioff specification in the SN74LVC2T45?

The Ioff specification in the SN74LVC2T45 limits leakage current to ±2 µA maximum when either VCCA or VCCB is at 0 V, ensuring safe partial-power-down operation. This prevents damaging backflow current into powered rails - essential for battery-backed subsystems, hot-plug interfaces, or systems with staggered power sequencing. The SN74LVC2T45 activates Ioff automatically upon rail collapse, requiring no external control or configuration.

Is the SN74LVC2T45 compatible with 1.65-V logic levels on both sides?

Yes, the SN74LVC2T45 is fully rated for operation with VCCA = 1.65 V and VCCB = 1.65 V. At this minimum supply, it maintains valid VIH (≥0.58 V) and VIL (≤0.49 V) thresholds, delivers ≥4 mA output drive, and sustains ≤17.7 ns propagation delay. This makes the SN74LVC2T45 suitable for ultra-low-voltage IoT sensor nodes and energy-harvesting systems where 1.65-V operation is mandated.