Texas Instruments SN74LVTH2245DW

Overview

SN74LVTH2245DW from Texas Instruments is an octal bus transceiver IC designed for 3.3-V VCC operation with mixed-mode 5-V input/output tolerance, enabling TTL-level interfacing between 3.3-V and 5-V data buses. It supports bidirectional data flow (A↔B), features bus-hold on all data inputs, Ioff for hot insertion, and B-port outputs with integrated 22-Ω series resistors. Used in industrial control backplanes and legacy system upgrades requiring level translation.

For engineers reviewing the SN74LVTH2245DW datasheet, SN74LVTH2245DW pinout, SN74LVTH2245DW application, or SN74LVTH2245DW equivalent, key selection criteria include its 20-pin SOIC (DW) package, 2.7–3.6-V supply range, ±12 mA B-port drive, 4.2 ns typical propagation delay (B→A), and support for unregulated battery operation down to 2.7 V.

Technical Context

This device implements asynchronous bidirectional bus transceivers with DIR-controlled direction and OE-gated 3-state output enable. Its dual-voltage interface architecture allows 5-V logic signals on A/B ports while operating from a 3.3-V supply, eliminating external level shifters in mixed-voltage systems.

The integrated bus-hold circuitry maintains valid logic states on floating inputs without pullup/pulldown resistors, and Ioff protection prevents current backflow during power-down. Power-up 3-state ensures high-impedance outputs during VCC ramping, supporting hot-plug capability in modular systems.

Key Specifications

Pinout & Package

SN74LVTH2245DW uses a 20-pin SOIC (DW) package with 7.5-mm body width, 1.27-mm lead pitch, and 2.65-mm maximum height per JEDEC MS-013. Pin 1 index area located at top-left corner with beveled edge marking.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC2245ADWR and SN74ALVCH162245DLR, the SN74LVTH2245DW uniquely delivers 5-V I/O tolerance, integrated bus-hold, and SOIC-20 compatibility-making it the sole option for retrofitting legacy 5-V systems with minimal layout change.

Availability

SN74LVTH2245DW is available at Aetrix Electronics and suitable for industrial backplane interfacing, legacy system voltage translation, and hot-swappable module communication requiring stable component supply and long-term obsolescence management.

Supply support for SN74LVTH2245DW 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 50 years of innovation in industrial, automotive, and communications markets.

The SN74LVTH2245DW belongs to TI's LVTH logic family, engineered specifically for mixed-voltage system interoperability and robust hot-insertion operation in mission-critical infrastructure equipment.

FAQ

What voltage levels can SN74LVTH2245DW tolerate on its A and B ports?

The SN74LVTH2245DW supports input voltages from −0.5 V to 7 V on both A and B ports, enabling direct connection to 5-V TTL systems while operating from a 3.3-V supply. This 5-V tolerance is intrinsic to the LVTH process and does not require external clamping or level-shifting circuitry. The SN74LVTH2245DW maintains full functionality across its specified VCC range of 2.7–3.6 V.

Does SN74LVTH2245DW require external pullup or pulldown resistors on its data inputs?

No, the SN74LVTH2245DW includes active bus-hold circuitry on all A and B port inputs, which maintains valid logic states on floating or unused pins without external resistors. Using pullup/pulldown resistors with bus-hold enabled is explicitly discouraged in the datasheet, as it may cause excessive current draw or logic instability. The SN74LVTH2245DW's bus-hold current is ±75 µA at 3 V, sufficient for noise-immune idle-state retention.

How does SN74LVTH2245DW support hot insertion in modular systems?

The SN74LVTH2245DW supports hot insertion through two complementary features: Ioff circuitry disables outputs when VCC = 0 V, preventing damaging current backflow from live backplanes; and power-up 3-state forces outputs into high-impedance during VCC ramping (0–1.5 V), avoiding bus contention. These features are production-tested per JESD 78 and validated for use in NEBS-compliant telecom chassis. The SN74LVTH2245DW requires no external sequencing components to achieve safe hot-swap behavior.

What is the purpose of the 22-Ω series resistors on the B-port outputs of SN74LVTH2245DW?

The B-port outputs of the SN74LVTH2245DW integrate 22-Ω series resistors to dampen signal reflections and reduce overshoot/undershoot on PCB traces, particularly in unterminated or medium-length bus runs. This built-in termination eliminates the need for discrete 22-Ω resistors near each B-port pin, simplifying layout and improving EMI performance. The SN74LVTH2245DW's A-port outputs lack this feature, reflecting its design for local 3.3-V bus driving where trace impedance matching is less critical.

Can SN74LVTH2245DW operate reliably below 3.3 V, such as from a depleting lithium battery?

Yes, the SN74LVTH2245DW is fully specified from 2.7 V to 3.6 V, making it suitable for battery-powered applications with declining supply voltage. At 2.7 V, it maintains 2 V VIH and 0.8 V VIL thresholds, ensuring TTL-compatible logic recognition, and delivers 24 mA sink current on the A port. Its typical VOL remains ≤0.5 V and VOH ≥2.4 V across the entire range. The SN74LVTH2245DW's guaranteed operation down to 2.7 V supports >30% deeper battery discharge before system reset.