STMicroelectronics 74ACT240TTR

Overview

74ACT240TTR from STMicroelectronics is an advanced high-speed CMOS octal bus buffer with 3-state inverted outputs, designed for bidirectional data bus isolation in memory address and control paths. It features 5 ns typical propagation delay at 5 V, ±24 mA symmetrical output drive, 4.5–5.5 V operating range, and TTL-compatible input thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V), enabling direct interface with TTL, NMOS, and CMOS logic in industrial control backplanes.

For engineers reviewing the 74ACT240TTR datasheet, 74ACT240TTR pinout, 74ACT240TTR application, or 74ACT240TTR equivalent, key selection criteria include 3-state output timing balance (tPLH ≅ tPHL), 50 Ω transmission line driving capability, latch-up immunity, ESD tolerance (2 kV), and TSSOP-20 package suitability for high-density PCB layouts.

Technical Context

The 74ACT240TTR implements two independent 4-bit inverting 3-state buffers, each controlled by a dedicated output-enable input (1G and 2G). Its C2MOS sub-micron silicon gate process enables low quiescent ICC (4 µA max) while sustaining fast switching with matched rise/fall delays.

All inputs and outputs integrate protection circuits for 2 kV HBM ESD immunity. The device operates across –55°C to +125°C with guaranteed AC performance under CL = 50 pF and RL = 500 Ω loads, supporting reliable signal integrity in noise-prone industrial environments.

Key Specifications

Pinout & Package

TSSOP-20 package: 6.4 mm × 6.5 mm body, 0.65 mm pitch, 1.1 mm height, lead-free and RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74ACT240PW and 74LCX240MTCX, the 74ACT240TTR delivers full 5 V TTL compatibility, superior ESD robustness (2 kV vs 1.5 kV typical), and extended temperature support - making it optimal for industrial and automotive 5 V bus isolation where interoperability and ruggedness are critical.

Availability

74ACT240TTR is available at Aetrix Electronics and suitable for industrial PLC backplanes, memory address buffering, and automotive body control modules requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for 74ACT240TTR 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, designing and manufacturing analog, digital, and mixed-signal ICs for industrial, automotive, and consumer markets.

The 74ACT series targets high-speed, low-power 5 V logic interoperability - specifically engineered to bridge legacy TTL systems with modern CMOS architectures while maintaining robustness in harsh environments.

FAQ

What is the maximum output current per pin for continuous DC operation?

The 74ACT240TTR supports ±24 mA DC output current per pin under guaranteed conditions (VOH/VOL tested at ±24 mA), with absolute maximum ratings permitting ±50 mA short-duration pulses. Continuous operation above ±24 mA risks exceeding VOL/VOH specifications and thermal limits in TSSOP-20 packaging.

Does the 74ACT240TTR support hot-plug or live-insertion on a powered bus?

Yes - its 2 kV HBM ESD protection, high-impedance 3-state outputs, and latch-up immunity allow safe insertion into a live 5 V bus. However, output-enable pins (1G/2G) must be held inactive (high) until power stabilization and bus initialization complete to prevent transient contention.

Can this device operate reliably at VCC = 4.5 V across the full –55°C to +125°C range?

Yes - all AC and DC specifications, including propagation delay (≤8.5 ns max), output drive (±24 mA min), and input thresholds, are fully characterized and guaranteed at VCC = 4.5 V over –55°C to +125°C per STMicroelectronics' recommended operating conditions table.

Is there a non-inverting version of this part in the same package and speed grade?

Yes - the 74ACT244TTR is the functional complement: octal non-inverting 3-state buffer, identical TSSOP-20 package, same 5 ns typical propagation delay, ±24 mA drive, and 4.5–5.5 V operation. Pinout differs (separate OE controls per 4-bit group), but footprint and thermal profile match.