Texas Instruments SN74LVTH540NS

Overview

SN74LVTH540NS from Texas Instruments is an octal buffer/driver IC designed for 3.3-V V_CC operation with mixed-mode 5-V input/output compatibility, 8-channel noninverting 3-state outputs, bus-hold inputs, and I_off support - used to drive memory address buses or system data lines in industrial control backplanes.

For engineers reviewing the SN74LVTH540NS datasheet, SN74LVTH540NS pinout, SN74LVTH540NS application, or SN74LVTH540NS equivalent, key selection considerations include its 2.7–3.6-V supply range, ±100 µA I_off, 64 mA I_OL, bus-hold functionality eliminating external resistors, and hot-insertion capability via power-up 3-state.

Technical Context

The SN74LVTH540NS implements dual active-low 3-state enable inputs (OE1 and OE2) wired as a 2-input AND gate: either high forces all eight Y outputs into high-impedance. Its bus-hold circuitry maintains valid logic states on undriven A inputs without external pullups, with ±500 µA dynamic hold current at 3.6 V.

It supports unregulated battery operation down to 2.7 V, features <0.8 V typical output ground bounce (V_OLP) at 3.3 V/25°C, and meets JESD 17 latch-up (>500 mA) and JESD 22 ESD standards (2000-V HBM, 200-V MM).

Key Specifications

Pinout & Package

SN74LVTH540NS uses a 20-pin SOP (Small Outline Package) with gull-wing leads, 0.65 mm pitch, and JEDEC MO-153 compliant footprint (body size 7.5 × 12.8 mm). Pin 1 is located at top-left corner with notch or index mark.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC540A, the SN74LVTH540NS adds critical 5-V input tolerance and bus-hold for legacy interoperability; versus SN74LVTH16244, it offers half the channel count in a smaller SOP-20 package ideal for incremental bus expansion.

Availability

SN74LVTH540NS is available at Aetrix Electronics and suitable for industrial control backplanes, memory subsystems, and hot-pluggable I/O modules requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for SN74LVTH540NS 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 industrial-grade interface ICs.

The SN74LVTH540NS belongs to TI's LVTH logic family, engineered for mixed-voltage system interfacing in harsh environments - targeting industrial automation, test equipment, and telecom infrastructure where reliability and voltage flexibility are critical.

FAQ

What is the maximum output sink current supported by SN74LVTH540NS?

The SN74LVTH540NS supports up to 64 mA per output (I_OL) at V_CC = 3 V and TA = 25°C, as specified in the recommended operating conditions table. This rating allows reliable driving of multiple TTL loads or moderate PCB trace capacitance without derating. The SN74LVTH540NS maintains this performance across its full 2.7–3.6-V V_CC range, making it suitable for variable-supply industrial applications.

Does SN74LVTH540NS require external pullup resistors on its inputs?

No, the SN74LVTH540NS does not require external pullup or pulldown resistors on its A1–A8 inputs due to integrated bus-hold circuitry. This feature actively maintains the last valid logic state on undriven inputs, with ±500 µA dynamic hold current at 3.6 V. Using external resistors with the SN74LVTH540NS is explicitly discouraged in the datasheet to avoid conflict with internal bus-hold behavior.

Can SN74LVTH540NS interface directly with 5-V logic devices?

Yes, the SN74LVTH540NS supports mixed-mode signal operation: its inputs tolerate 5-V TTL voltage levels while operating from a 3.3-V V_CC, and its outputs deliver TTL-compatible VOH (≥2.0 V) and VOL (≤0.55 V) under rated load. This eliminates the need for external level translators when connecting to legacy 5-V peripherals such as older SRAM, CPLDs, or discrete logic families.

What thermal performance can be expected from SN74LVTH540NS in its NS package?

The SN74LVTH540NS in the SOP-20 (NS) package has a junction-to-ambient thermal resistance (θ_JA) of 60°C/W under standard JEDEC test conditions. This allows the device to dissipate approximately 330 mW before reaching a 20°C temperature rise above ambient, supporting continuous 8-output switching in compact industrial PCB layouts with minimal copper pour.

How does SN74LVTH540NS support hot-insertion in modular systems?

The SN74LVTH540NS supports hot-insertion through two complementary features: I_off circuitry disables outputs and blocks current backflow when V_CC = 0 V, and power-up 3-state holds all Y outputs in high-impedance until V_CC exceeds 1.5 V. These mechanisms prevent bus contention and damaging current flow during live module insertion - a requirement verified per JESD 17 latch-up and JESD 22 ESD standards.