Texas Instruments SN74LVC543ADW

Overview

SN74LVC543ADW from Texas Instruments is an octal registered transceiver with 3-state outputs, designed for bidirectional data flow between two 8-bit buses in mixed-voltage systems. It operates from 1.65 V to 3.6 V, supports 5.5-V-tolerant inputs, delivers 7-ns max propagation delay at 3.3 V, and features independent A-to-B and B-to-A latch-enable and output-enable controls. It enables level translation in 3.3-V/5-V interfacing applications such as microcontroller bus expansion.

For engineers reviewing the SN74LVC543ADW datasheet, SN74LVC543ADW pinout, SN74LVC543ADW application, or SN74LVC543ADW equivalent, key selection criteria include its dual-directional latching architecture, Ioff partial-power-down support, 24-pin SOIC (DW) package compatibility, and verified 3.3-V/5-V mixed-mode signal handling capability.

Technical Context

This device implements two independent 8-bit D-type latch banks - one for A-to-B and one for B-to-A data paths - each with dedicated CE, LE, and OE control signals. Its logic diagram confirms non-inverting data transfer with separate enable sequencing per direction, and the function table validates that both directions operate under identical control timing constraints.

The SN74LVC543ADW integrates Ioff circuitry to disable outputs during power-down, preventing backflow current, and supports input voltages up to 5.5 V regardless of VCC (1.65–3.6 V), enabling robust interfacing between legacy 5-V logic and modern low-voltage domains without external level shifters.

Key Specifications

Pinout & Package

SN74LVC543ADW uses a 24-pin SOIC (DW) package with 300-mil body width, JEDEC MO-153 compliant footprint, and 0.65-mm lead pitch. Thermal resistance θJA is 46°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC543APW and SN74LVCH16543ADGG, the SN74LVC543ADW offers optimal thermal performance (θJA = 46°C/W) and proven manufacturability in SOIC-DW, making it preferred for industrial designs requiring reliability across wide temperature ranges and long-term supply stability.

Availability

SN74LVC543ADW is available at Aetrix Electronics and suitable for industrial PLC backplanes, FPGA-to-ASIC interface boards, and microcontroller bus expansion modules requiring stable component supply, long-lifecycle support, and RoHS-compliant SOIC packaging.

Supply support for SN74LVC543ADW 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 expertise in high-reliability interface ICs and broad automotive/industrial qualification.

The SN74LVC543ADW belongs to TI's LVC logic family, engineered for low-voltage, high-speed bidirectional data transfer in mixed-signal systems where voltage translation, latch synchronization, and power-aware design are critical.

FAQ

What is the maximum clock frequency supported by SN74LVC543ADW?

The SN74LVC543ADW does not contain an internal clock; it is a latch-based transceiver controlled by asynchronous enable and latch signals. Its usable data rate depends on external timing: with 7-ns max propagation delay at 3.3 V, it supports bus toggle rates up to ~70 MHz in properly terminated systems, assuming setup/hold times (1.6 ns su, 2.1 ns h) are met by the controlling logic.

Can SN74LVC543ADW interface a 5-V microcontroller with a 3.3-V FPGA?

Yes. The SN74LVC543ADW accepts 5.5-V-tolerant inputs while operating from a 3.3-V VCC, allowing direct connection of 5-V microcontroller outputs to its A or B ports. Its 3.3-V-compatible outputs drive FPGA I/O banks safely, and Ioff protection prevents damage during power sequencing mismatches - a core design intent confirmed in TI's mixed-mode operation specification.

Does SN74LVC543ADW require external pull-up resistors on OE pins?

TI recommends tying OEAB and OEBA to VCC through a pull-up resistor during power-up/down to ensure outputs remain in high-impedance state. The minimum resistor value depends on the driver's sink capability; for standard CMOS drivers, 10-kΩ is typical. This requirement is explicitly stated in the datasheet to prevent undefined output states during supply ramping.

Is SN74LVC543ADW pin-compatible with older 74-series transceivers like 74LS245?

No. The SN74LVC543ADW has a distinct 24-pin SOIC pinout optimized for dual-directional latching (e.g., separate LEAB/LEBA, CEAB/CEBA), unlike the 20-pin 74LS245's single-directional, non-latched architecture. Pin assignments, control logic, voltage ranges, and electrical characteristics are incompatible - direct replacement would require PCB redesign and firmware updates.

What is the latch behavior of SN74LVC543ADW during a low-to-high transition of LEAB?

When LEAB transitions low-to-high while CEAB is low, the SN74LVC543ADW captures and holds the instantaneous logic levels present on A1–A8 inputs, storing them in the A-to-B latches. Subsequent changes on A inputs do not affect the latched values until the next LEAB↑ event. This behavior is defined in the function table and logic diagram, and is fundamental to its use in synchronous bus handshaking protocols.