Texas Instruments SN74LVTH543DBR

Overview

SN74LVTH543DBR from Texas Instruments is an octal bus transceiver with dual-direction latched data flow, supporting mixed-mode 3.3-V VCC operation while interfacing to 5-V TTL systems. It features independent A-to-B and B-to-A latch-enable (LEAB/LEBA) and output-enable (OEAB/OEBA) controls, bus-hold on all data inputs, Ioff for hot insertion, and operates down to 2.7 V. It is used in voltage-level translation between 3.3-V logic domains and legacy 5-V buses in industrial control backplanes.

For engineers reviewing the SN74LVTH543DBR datasheet, SN74LVTH543DBR pinout, SN74LVTH543DBR application, or SN74LVTH543DBR equivalent, key selection considerations include its 24-pin SSOP package, bidirectional latched transceiver architecture, 3.3-V supply with 5-V tolerant inputs, bus-hold functionality eliminating external resistors, and hot-insertion support via Ioff and power-up 3-state.

Technical Context

The SN74LVTH543DBR implements two independent sets of D-type latches-one for A-to-B and one for B-to-A data paths-each controlled by dedicated CE, LE, and OE signals. Its bus-hold circuitry actively maintains valid logic states on undriven A/B port inputs without external pull resistors.

It supports true hot insertion through Ioff (outputs disabled when VCC = 0 V) and power-up 3-state (outputs remain high-impedance during power ramping). Input tolerance extends to 5.5 V regardless of VCC, enabling robust interfacing with higher-voltage systems.

Key Specifications

Pinout & Package

SN74LVTH543DBR uses a 24-pin SSOP (Shrink Small-Outline Package) with 0.65 mm pitch, 7.9 mm × 4.5 mm body, and 1.2 mm max height. Pin 1 is located in quadrant Q1 per tape-and-reel orientation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVTH543DBR, SN74LVT543DBR reduces integration by omitting bus-hold and hot-insertion features, increasing BOM and layout effort; SN74LVTH16543DGGR scales channel count but demands significant PCB redesign - making SN74LVTH543DBR optimal for space-constrained 8-bit bidirectional translation with zero-compromise robustness.

Availability

SN74LVTH543DBR is available at Aetrix Electronics and suitable for industrial backplane interfaces, hot-swappable I/O modules, and low-voltage embedded bus translation requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for SN74LVTH543DBR 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 logic solutions, with decades of heritage in high-reliability interface ICs.

The SN74LVTH543DBR belongs to TI's LVTH logic family, engineered for mixed-voltage system interoperability and rugged industrial deployment - specifically targeting 3.3-V core logic interfacing to legacy 5-V infrastructure.

FAQ

What is the operating voltage range for SN74LVTH543DBR?

The SN74LVTH543DBR operates from 2.7 V to 3.6 V on VCC, with full specification compliance across this range. Its inputs tolerate up to 5.5 V regardless of VCC level, enabling direct connection to 5-V TTL sources without external level-shifting components. This mixed-mode capability is intrinsic to the LVTH family architecture and confirmed in the recommended operating conditions table of the SCBS704F datasheet.

Does SN74LVTH543DBR support hot insertion?

Yes, SN74LVTH543DBR supports hot insertion via two integrated features: Ioff circuitry disables outputs when VCC = 0 V to prevent back-current flow, and power-up 3-state holds outputs in high-impedance until VCC exceeds 1.5 V. These functions are explicitly validated in the datasheet's "Support Hot Insertion" feature list and absolute maximum ratings section, making SN74LVTH543DBR suitable for modular industrial systems requiring live module replacement.

What package type is used for SN74LVTH543DBR?

SN74LVTH543DBR uses a 24-pin SSOP (Shrink Small-Outline Package), designated DB package per TI's ordering information. Its dimensions are 7.9 mm × 4.5 mm with 0.65 mm lead pitch and 1.2 mm max height. The package drawing MO-150 and mechanical data MSSO002E confirm pin 1 location in quadrant Q1 for tape-and-reel orientation, and thermal resistance θJA is specified as 63°C/W.

How does bus-hold functionality work on SN74LVTH543DBR?

SN74LVTH543DBR integrates active bus-hold circuitry on all A1–A8 and B1–B8 data terminals, maintaining undriven inputs at their last-valid logic state using ±500 µA dynamic current (at VCC = 3.6 V). This eliminates the need for external pullup or pulldown resistors, reducing component count and PCB area. The datasheet explicitly warns against using external resistors with bus-hold enabled, as they may conflict with internal clamping behavior.

Can SN74LVTH543DBR replace SN74LVT543DBR in an existing design?

SN74LVTH543DBR is pin-compatible with SN74LVT543DBR and shares identical DC and AC specifications except for bus-hold and hot-insertion features. Replacing SN74LVT543DBR with SN74LVTH543DBR adds bus-hold (removing external resistors) and Ioff/power-up 3-state (enabling hot-swap), with no layout changes required. However, if the original design relies on floating inputs being pulled externally, bus-hold may alter default states and require validation.