Texas Instruments SN74LVC240APWRE4

Overview

SN74LVC240APWRE4 from Texas Instruments is an octal noninverting buffer/driver with dual 3-state output banks, operating from 1.65V to 3.6V supply, supporting 5.5V-tolerant inputs, delivering ≤6.5ns propagation delay at 3.3V, and enabling mixed-mode signal interfacing (e.g., 5V logic driving 3.3V bus). It is used in digital signal redriving, transmission-line termination, and controller reset hold applications.

For engineers reviewing the SN74LVC240APWRE4 datasheet, SN74LVC240APWRE4 pinout, SN74LVC240APWRE4 application, or SN74LVC240APWRE4 equivalent, key selection criteria include 3-state bank control timing, Ioff-enabled live insertion, overvoltage-tolerant inputs, thermal performance in TSSOP-20, and compatibility with 1.8V/2.5V/3.3V logic families.

Technical Context

The SN74LVC240APWRE4 integrates eight CMOS buffer channels split into two independent 4-channel banks (Bank 1: pins 1A1–1A4 / 1Y1–1Y4; Bank 2: pins 2A1–2A4 / 2Y1–2Y4), each controlled by a dedicated active-low output enable (1OE on pin 1, 2OE on pin 19). Its balanced push-pull outputs drive high/low states symmetrically and enter high-impedance when disabled.

It implements partial-power-down protection (Ioff) that disables all outputs at 0V VCC, supports 5.5V input tolerance regardless of VCC level (1.65–3.6V), and features Schmitt-trigger–free standard CMOS inputs requiring fast transitions (≤6 ns/V slew rate) to avoid oscillation or excess power draw.

Key Specifications

Pinout & Package

TSSOP-20 (PW) package: 6.5mm × 6.4mm body with 0.65mm pitch; thermally enhanced for surface-mount reliability in space-constrained PCB layouts.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal 3-state buffer applications.

Compared with SN74LVC240APWRE4, SN74LVC244APWRE4 simplifies enable control at the cost of bank-level isolation, while 74LVC240ADTR2G offers second-source assurance with near-identical electrical behavior - both require validation of timing margins and Ioff leakage in hot-swap contexts.

Availability

SN74LVC240APWRE4 is available at Aetrix Electronics and suitable for industrial bus redriving, digital controller reset hold, LED indicator driving, and transmission-line termination requiring stable component supply across extended temperature and mixed-voltage designs.

Supply support for SN74LVC240APWRE4 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 leadership in high-reliability logic families.

The SN74LVC240APWRE4 belongs to the LVC (Low-Voltage CMOS) logic family, designed specifically for low-voltage, high-speed, mixed-signal interfacing in portable, industrial, and automotive electronics.

FAQ

What is the maximum operating frequency supported by the SN74LVC240APWRE4?

The SN74LVC240APWRE4 does not specify a hard maximum clock frequency, but its 6.5ns propagation delay at 3.3V supports reliable operation up to ~100MHz in point-to-point redrive configurations. Actual usable frequency depends on load capacitance (≤50pF recommended), trace impedance, and signal integrity design - for 50Ω transmission lines, it sustains clean 100Mbps NRZ data without equalization.

Can the SN74LVC240APWRE4 safely interface a 5V microcontroller with a 3.3V FPGA?

Yes. The SN74LVC240APWRE4 accepts inputs up to 5.5V regardless of VCC level (1.65–3.6V), making it ideal for level-shifting from 5V logic to 3.3V domains. When powered at 3.3V, its outputs swing rail-to-rail (0V–3.3V), fully compatible with 3.3V FPGA I/O standards such as LVTTL or LVCMOS33 - no external resistors or translators needed.

How should unused inputs be handled on the SN74LVC240APWRE4?

All unused inputs on the SN74LVC240APWRE4 must be terminated to either VCC or GND - floating CMOS inputs cause excessive current draw and potential oscillation. A 10kΩ pull-up or pull-down resistor is recommended for uncommitted inputs; direct connection is acceptable if the signal is permanently inactive. This applies to all A and OE pins not in use.

Does the SN74LVC240APWRE4 support hot-plug or live-insertion applications?

Yes. The SN74LVC240APWRE4 includes Ioff circuitry that disables all outputs when VCC = 0V, limiting off-state leakage to ±10μA. This prevents back-driving of powered buses and protects upstream components during insertion into live backplanes - a key requirement for modular industrial controllers and telecom line cards.

What is the thermal resistance (RθJA) of the SN74LVC240APWRE4 in its TSSOP-20 package?

The SN74LVC240APWRE4 in the PW (TSSOP-20) package has a junction-to-ambient thermal resistance (RθJA) of 120.3°C/W under standard JEDEC test conditions. This value assumes a 2-layer board with 1-in² copper pour; actual thermal performance improves significantly with internal ground/power planes and thermal vias - derating is advised above 85°C ambient in high-density layouts.