Texas Instruments SN74LVC543APWT

Overview

SN74LVC543APWT 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, accepts 5.5-V-tolerant inputs, and delivers 7-ns max propagation delay at 3.3 V. Its Ioff support enables partial-power-down operation in hot-swap or power-gated applications.

For engineers reviewing the SN74LVC543APWT datasheet, SN74LVC543APWT pinout, SN74LVC543APWT application, or SN74LVC543APWT equivalent, key selection criteria include independent A↔B latch-enable/output-enable control, 3.3-V/5-V mixed-mode interface capability, 24-pin TSSOP package compatibility, and guaranteed 3-state output isolation during power sequencing.

Technical Context

The SN74LVC543APWT implements dual 8-bit D-type latches-one for A-to-B and one for B-to-A data paths-with separate CEAB/CEBA, LEAB/LEBA, and OEAB/OEBA control signals. This architecture enables asynchronous, directionally independent register staging and output gating.

Its Ioff circuitry actively disables outputs when VCC = 0 V, preventing back-current flow in partial-power-down scenarios. Input tolerance up to 5.5 V allows direct interfacing with legacy 5-V logic while powered from 3.3-V or lower rails-no level-shifter required.

Key Specifications

Pinout & Package

TSSOP-24 (PW) package: 7.8 mm × 4.4 mm, 1.2 mm max height, 0.65 mm lead pitch, exposed thermal pad optional per layout guidelines.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC245APW and SN74ALVC164245GR, the SN74LVC543APWT uniquely provides octal registered storage with independent A↔B control-critical for synchronous bus arbitration, pipeline staging, and deterministic timing in embedded controllers and test systems.

Availability

SN74LVC543APWT is available at Aetrix Electronics and suitable for industrial PLC backplane interfaces, embedded FPGA I/O expansion, and automotive body control modules requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant TSSOP packaging.

Supply support for SN74LVC543APWT 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 over 50 years of innovation in high-reliability interface and power management ICs.

The SN74LVC543APWT belongs to TI's LVC logic family-designed specifically for low-voltage, high-speed, mixed-signal system interfacing with emphasis on voltage translation, bus isolation, and power-aware operation.

FAQ

What is the maximum operating frequency supported by the SN74LVC543APWT?

The SN74LVC543APWT does not specify a maximum clock frequency, as it is not a clocked sequential device. Instead, its timing is governed by propagation delay (tpd ≤ 7 ns at 3.3 V) and setup/hold requirements (tsu = 1.6 ns, th = 2.1 ns). System-level maximum data rate depends on bus loading and controller timing margins-but reliable operation up to 100 MHz is achievable in well-designed 50-Ω-terminated parallel interfaces using the SN74LVC543APWT.

Can the SN74LVC543APWT be used to interface a 5-V microcontroller with a 3.3-V FPGA?

Yes, the SN74LVC543APWT supports this exact use case. Its 5.5-V-tolerant inputs accept 5-V logic levels while operating from a 3.3-V VCC rail, and its outputs swing rail-to-rail within the 3.3-V domain. No external level-shifting components are required, and Ioff protection ensures safe operation during FPGA power-up sequences where the SN74LVC543APWT may be unpowered.

Does the SN74LVC543APWT support hot-swap or live-insertion applications?

Yes, the SN74LVC543APWT supports hot-swap applications via its Ioff feature. When VCC = 0 V, the Ioff circuitry disables all outputs, limiting off-state leakage to ±10 µA-even if 5.5-V signals are present on inputs or I/O pins. This prevents damaging back-current flow into a powered-down board section, satisfying JEDEC JESD78 latch-up and IEC 61000-4-2 ESD robustness requirements for modular systems.

What is the recommended pull-up resistor value for OEAB/OEBA on the SN74LVC543APWT during power-up?

TI recommends tying OEAB and OEBA to VCC through a pull-up resistor to ensure high-impedance outputs during power-up. The minimum resistor value is determined by the current-sinking capability of the driving source. For typical microcontroller GPIOs (±20 mA), a 10-kΩ resistor provides sufficient noise immunity and fast turn-on while limiting current to <0.33 mA at 3.3 V-ensuring reliable 3-state assertion before logic initialization completes on the SN74LVC543APWT.

How does the latch-enable behavior differ between LEAB and LEBA on the SN74LVC543APWT?

LEAB controls the A-to-B latch: when LEAB is low, A1–A8 inputs pass transparently to the A-latch outputs; a rising edge stores the current A-bus state. LEBA controls the B-to-A latch identically but for the reverse path-low enables transparency from B1–B8 to the B-latch, and a rising edge captures B-bus data. Both operate independently, allowing simultaneous staging of data in both directions without interference, which is essential for full-duplex bus arbitration in the SN74LVC543APWT.