Texas Instruments SN74LVC540AQDWREP

Overview

SN74LVC540AQDWREP from Texas Instruments is an octal buffer/driver with 3-state outputs, designed for 2.0 V to 3.6 V V_CC operation. It features dual active-low output-enable inputs (OE1, OE2), 8 noninverting channels, I_off support for partial-power-down mode, and mixed-mode signal operation enabling 5-V input tolerance with 3.3-V V_CC. It is used to drive bus lines or buffer memory address registers in industrial control and data acquisition systems.

For engineers reviewing the SN74LVC540AQDWREP datasheet, SN74LVC540AQDWREP pinout, SN74LVC540AQDWREP application, or SN74LVC540AQDWREP equivalent, key selection criteria include 3-state timing (t_pd = 5.3 ns @ 3.3 V), I_off protection, 5.5-V-tolerant inputs, and SOIC-20 packaging for legacy board compatibility.

Technical Context

The SN74LVC540AQDWREP implements a dual-gated 3-state control architecture: both OE1 and OE2 must be low for outputs Y1–Y8 to drive; either high forces all outputs into high-impedance. Its logic diagram confirms noninverting buffering with no internal inversion.

It supports mixed-voltage interfacing via 5.5-V-tolerant inputs while operating from 2.0–3.6 V V_CC, and includes I_off circuitry that disables outputs during power-down to prevent backflow current-critical for hot-swap and partial-power-down systems.

Key Specifications

Pinout & Package

SN74LVC540AQDWREP uses a 20-pin SOIC (DW) package with 0.300″ body width and standard JEDEC MS-013AC outline. Pin spacing is 0.050″ (1.27 mm), and thermal resistance θ_JA is 58°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC540AQDWREP, SN74LVC541AQDWREP offers simpler enable control but reduced bus arbitration flexibility, while SN74LVCH16540AQRGYRQ1 delivers higher performance and automotive qualification at the cost of non-compatible packaging and increased complexity.

Availability

SN74LVC540AQDWREP is available at Aetrix Electronics and suitable for industrial PLC backplanes, avionics data bus interfaces, and ruggedized medical imaging controllers requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for SN74LVC540AQDWREP 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 company headquartered in Dallas, Texas, specializing in analog, embedded processing, and logic ICs for industrial, automotive, and communications markets.

The SN74LVC540A-EP product line delivers enhanced plastic (EP) versions of standard LVC logic with extended temperature range (–40°C to +125°C), controlled baseline manufacturing, and DMS support for long-lifecycle industrial and defense applications.

FAQ

What is the maximum input voltage rating for SN74LVC540AQDWREP?

The SN74LVC540AQDWREP supports input voltages up to 5.5 V across the full operating temperature range, independent of V_CC. This allows direct interfacing with 5-V logic families without external level-shifting circuitry. The absolute maximum rating is 6.5 V, but sustained operation above 5.5 V is not recommended per TI's recommended operating conditions table.

Does SN74LVC540AQDWREP support partial-power-down operation?

Yes, SN74LVC540AQDWREP includes I_off circuitry that actively disables outputs when V_CC = 0 V, preventing damaging current backflow from powered inputs into the unpowered device. This feature is fully characterized over –40°C to +125°C and is critical for hot-swap and multi-rail power sequencing applications.

What is the propagation delay of SN74LVC540AQDWREP at 3.3 V?

The maximum propagation delay (t_pd) of SN74LVC540AQDWREP is 5.3 ns when V_CC = 3.3 V and operating at TA = 25°C. Typical values are lower (e.g., 3.8 ns), and the parameter is guaranteed across the full –40°C to +125°C range per the switching characteristics table in the official datasheet SCAS747A.

How are the output-enable inputs configured on SN74LVC540AQDWREP?

SN74LVC540AQDWREP uses two active-low output-enable inputs - OE1 (pin 1) and OE2 (pin 19) - wired as a 2-input AND gate. Both must be low for outputs Y1–Y8 to drive; if either is high, all outputs enter high-impedance state. This dual-OE structure enables flexible bus arbitration and hierarchical enable schemes in complex digital systems.

Is SN74LVC540AQDWREP pin-compatible with commercial-grade SN74LVC540A?

Yes, SN74LVC540AQDWREP shares identical pinout, electrical behavior, and SOIC-20 (DW) package dimensions with the commercial SN74LVC540A, differing only in extended temperature qualification (–40°C to +125°C), enhanced manufacturing pedigree, and EP-specific handling of moisture sensitivity (MSL Level-1). No PCB layout changes are required for drop-in replacement.