Texas Instruments SN74LVTH540PW

Overview

SN74LVTH540PW from Texas Instruments is an octal buffer/driver IC designed for 3.3-V V_CC operation with 5-V tolerant inputs and outputs, supporting mixed-mode signal interfacing between 3.3-V logic and 5-V systems. It features dual active-low 3-state enable inputs (OE1, OE2), bus-hold on all eight data inputs, I_off protection for hot insertion, and operates down to 2.7 V for unregulated battery applications.

For engineers reviewing the SN74LVTH540PW datasheet, SN74LVTH540PW pinout, SN74LVTH540PW application, or SN74LVTH540PW equivalent, this device is selected for bidirectional bus buffering in industrial control backplanes, memory address register driving, and legacy TTL-to-LVCMOS level translation where output drive strength (64 mA sink), low ground bounce (<0.8 V), and power-up 3-state behavior are critical.

Technical Context

The SN74LVTH540PW implements an octal noninverting buffer architecture with two independent AND-gated 3-state controls (OE1 and OE2), where either high input forces all Y outputs into high-impedance. Its bus-hold circuitry actively maintains valid logic states on undriven A inputs without external resistors, eliminating floating node risks in unterminated buses.

It supports hot insertion via I_off (±100 µA at V_CC = 0) and power-up 3-state behavior-outputs remain high-Z during V_CC ramp from 0 to 1.5 V and require OE pullup only above that threshold. Absolute input voltage tolerance extends to 7 V, enabling direct connection to 5-V sources while powered from 3.3 V.

Key Specifications

Pinout & Package

TSSOP-20 (PW) package: 6.5 mm × 4.4 mm body, 0.65 mm lead pitch, 1.2 mm max height, gull-wing leads, RoHS-compliant NiPdAu finish, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC541APW and 74ALVC16244DGGR, the SN74LVTH540PW uniquely combines 5-V I/O tolerance, integrated bus-hold, and hot-insertion readiness-making it irreplaceable in mixed-voltage industrial backplanes where reliability under voltage mismatch and undriven conditions is non-negotiable.

Availability

SN74LVTH540PW is available at Aetrix Electronics and suitable for industrial automation backplanes, memory subsystem interfaces, and legacy system upgrade kits requiring stable component supply with full lifecycle traceability and long-term obsolescence management.

Supply support for SN74LVTH540PW 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 connectivity technologies, with over 50 years of innovation in industrial-grade logic and interface solutions.

The SN74LVTH540PW belongs to TI's LVTH logic family, engineered specifically for robust mixed-voltage interfacing in harsh industrial and automotive environments where signal integrity, hot-swap safety, and wide supply tolerance are mandatory.

FAQ

What is the maximum input voltage rating for SN74LVTH540PW?

The SN74LVTH540PW supports an absolute maximum input voltage of 7 V on any pin, including data inputs (A1–A8) and enable inputs (OE1, OE2), regardless of V_CC state. This allows direct connection to 5-V sources while operating from a 3.3-V supply, making the SN74LVTH540PW ideal for mixed-voltage system interfacing without external clamping diodes or level shifters.

Does SN74LVTH540PW support hot insertion, and how is it implemented?

Yes, SN74LVTH540PW supports hot insertion via two mechanisms: I_off circuitry limits current to ±100 µA when V_CC = 0, preventing backflow into powered systems; and power-up 3-state ensures outputs remain high-impedance until V_CC exceeds 1.5 V. These features make SN74LVTH540PW suitable for live backplane replacement in industrial PLCs and telecom line cards without disrupting adjacent circuitry.

How does the bus-hold function work on SN74LVTH540PW inputs?

The SN74LVTH540PW integrates active bus-hold circuitry on all eight A-inputs, drawing ±500 µA at V_CC = 3.6 V to maintain the last-valid logic state when inputs float. This eliminates the need for external 10-kΩ pull-up/pull-down resistors, reducing BOM count and PCB area. Bus-hold is always enabled and cannot be disabled-ensuring deterministic behavior in unterminated or partially loaded buses where the SN74LVTH540PW is deployed.

What is the recommended layout practice for SN74LVTH540PW to minimize ground bounce?

To minimize ground bounce in SN74LVTH540PW, place a 0.1-µF ceramic bypass capacitor between V_CC (Pin 10) and GND (Pin 9) within 10 mm of the package, use solid ground plane beneath the TSSOP-20 footprint, and route Y-output traces away from sensitive analog sections. The SN74LVTH540PW's specified V_OLP < 0.8 V assumes these practices-failure to implement them may degrade noise margin in high-fanout or fast-switching configurations.

Can SN74LVTH540PW drive standard TTL loads directly?

Yes, SN74LVTH540PW can directly drive standard TTL loads: its I_OL = 64 mA and VOL ≤ 0.55 V at 3.3 V meet or exceed TTL input low-level voltage (V_IL ≤ 0.8 V) and current (I_IL ≤ −1.6 mA) requirements. When driving multiple TTL inputs, verify total sink current remains within 64 mA per Y-output; the SN74LVTH540PW's 5-V tolerant outputs ensure compatibility even if downstream devices operate at 5 V.