Texas Instruments SN74LVC543APW

Overview

SN74LVC543APW from Texas Instruments is an octal registered transceiver with 3-state outputs, designed for bidirectional data flow between two 8-bit buses in 1.65-V to 3.6-V systems. It features independent A-to-B and B-to-A latch-enable (LEAB/LEBA) and output-enable (OEAB/OEBA) controls, 7-ns max propagation delay at 3.3 V, and 5.5-V-tolerant inputs-enabling mixed-mode 3.3-V/5-V interfacing in industrial control backplanes.

For engineers reviewing the SN74LVC543APW datasheet, SN74LVC543APW pinout, SN74LVC543APW application, or SN74LVC543APW equivalent, key selection criteria include its dual-direction latching architecture, Ioff partial-power-down support, 24-pin TSSOP package, and guaranteed 3.6-V supply operation with 5-V input compatibility.

Technical Context

The SN74LVC543APW implements two independent 8-bit D-type latch banks-one for A-to-B and one for B-to-A data paths-with separate CE (chip-enable), LE (latch-enable), and OE (output-enable) signals per direction. Its logic supports transparent latch mode on LE low and storage mode on LE rising edge, while OE controls 3-state output drivers.

It integrates Ioff circuitry to disable outputs during power-down, preventing backflow current when VCC = 0 V, and accepts input voltages up to 5.5 V regardless of VCC level-enabling direct interface between 5-V legacy peripherals and 3.3-V logic domains without external level shifters.

Key Specifications

Pinout & Package

TSSOP-24 (PW) package: 7.9 mm × 4.5 mm × 1.2 mm body, 0.65-mm lead pitch, exposed pad optional, RoHS-compliant NIPDAU finish, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC543APW, SN74LVC541APW reduces pin count and cost for unidirectional use cases but sacrifices bidirectional latching capability, while SN74ALVC164245DGGR offers wider data paths and true dual-supply translation but requires external timing control and occupies a larger 48-pin TSSOP footprint.

Availability

SN74LVC543APW is available at Aetrix Electronics and suitable for industrial backplane interfaces, PLC I/O modules, and automated test equipment requiring stable component supply, long-term lifecycle support, and RoHS-compliant TSSOP packaging.

Supply support for SN74LVC543APW 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 delivering analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.

The SN74LVC543APW belongs to TI's LVC logic family-designed specifically for low-voltage, high-speed, mixed-signal interfacing in space-constrained industrial and test systems.

FAQ

What is the maximum operating frequency supported by the SN74LVC543APW?

The SN74LVC543APW does not specify a maximum clock frequency, as it is a latch-based transceiver-not a clocked register. Its timing is governed by setup/hold requirements (tsu = 1.6 ns, th = 2.1 ns) and propagation delay (tpd ≤ 7 ns at 3.3 V). System-level data rate depends on external control signal timing, not an internal clock. For SN74LVC543APW, design margin should ensure LE and CE transitions meet these nanosecond-scale constraints.

Can the SN74LVC543APW operate with a 1.8-V supply and still accept 5-V inputs?

Yes. The SN74LVC543APW supports VCC from 1.65 V to 3.6 V and explicitly tolerates input voltages up to 5.5 V across that entire supply range. At VCC = 1.8 V, inputs remain 5-V-tolerant, enabling direct connection to 5-V sources without level shifters-critical for brown-out tolerant designs. This behavior is confirmed in the Recommended Operating Conditions table and Input Voltage specification (VI = 0 to 5.5 V).

Does the SN74LVC543APW support hot-swap or partial-power-down operation?

Yes. The SN74LVC543APW includes Ioff circuitry that disables all outputs when VCC = 0 V, preventing damaging current backflow from live buses into the unpowered device. This feature is validated per JEDEC JESD 78 and enables safe insertion/removal in modular systems. For SN74LVC543APW, tie OEAB and OEBA to VCC via pullup resistors to guarantee high-impedance state during power transitions.

What is the thermal resistance (θJA) of the SN74LVC543APW in its TSSOP-24 package?

The SN74LVC543APW in the PW (TSSOP-24) package has a junction-to-ambient thermal resistance (θJA) of 88°C/W, as specified in the Absolute Maximum Ratings table. This value assumes standard JEDEC PCB mounting conditions (2-layer board, 1-in² copper area). For sustained 24-mA output loading, temperature rise remains within safe limits below 85°C ambient-making SN74LVC543APW suitable for convection-cooled industrial enclosures.

How are the latch-enable and output-enable functions coordinated for A-to-B data flow in the SN74LVC543APW?

In A-to-B mode, CEAB must be low to activate the path. When LEAB is low, the A inputs pass transparently to the A-latch outputs; a rising edge on LEAB captures and holds the A-data. With CEAB and OEAB both low, the B outputs reflect the stored A-latch values. If OEAB goes high, B outputs enter high-impedance-regardless of LEAB or CEAB state. This precise sequencing is defined in the Function Table and applies identically to SN74LVC543APW's B-to-A path using CEBA, LEBA, and OEBA.