STMicroelectronics 74VHCT240AMTR

Overview

74VHCT240AMTR from STMicroelectronics is an octal 3-state inverting bus buffer with dual independent output-enable controls (1G, 2G), operating at 4.5–5.5 V, delivering 5.4 ns typical propagation delay, ±8 mA symmetrical output drive, and 4 µA max quiescent current at 25°C - used in memory address/data bus isolation and level translation between 5V TTL and 3V logic domains.

For engineers reviewing the 74VHCT240AMTR datasheet, 74VHCT240AMTR pinout, 74VHCT240AMTR application, or 74VHCT240AMTR equivalent, key selection criteria include TTL-compatible input thresholds (VIH ≥ 2 V, VIL ≤ 0.8 V), power-down protection enabling 0–7 V input tolerance regardless of VCC, high-impedance output leakage ≤ ±2.5 µA, and guaranteed operation across –55°C to +125°C.

Technical Context

This device implements two independent 4-bit inverting buffers, each controlled by its own active-low enable (1G, 2G). All inputs feature TTL threshold detection and ESD protection (2 kV HBM), while outputs support true 3-state behavior with matched rise/fall delays (tPLH ≅ tPHL) and low noise (VOLP ≤ 0.9 V).

It uses sub-micron C2MOS technology for latch-up immunity and operates with rail-to-rail input tolerance (–0.5 V to VCC + 0.5 V), enabling safe hot-swap and mixed-voltage interfacing without external clamping. The design supports simultaneous switching of up to seven outputs under defined load conditions (CL = 50 pF, RL = 1 kΩ).

Key Specifications

Pinout & Package

74VHCT240AMTR is housed in a 20-pin SOIC (Small Outline Integrated Circuit) package, tape-and-reel format (MTR suffix), with 1.27 mm pitch, body width 7.5 mm, and JEDEC MS-013 compliant dimensions.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74VHCT240APW and 74VHC240N, the 74VHCT240AMTR uniquely combines SOIC manufacturability, full TTL input compatibility, and 0–7 V input tolerance - making it optimal for industrial retrofits and mixed-signal control hubs where reliability and legacy integration outweigh miniaturization needs.

Availability

74VHCT240AMTR is available at Aetrix Electronics and suitable for memory address buffering, industrial PLC I/O expansion, and legacy system upgrades requiring stable component supply, long-lifecycle support, and traceable sourcing.

Supply support for 74VHCT240AMTR 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, Switzerland, designing and manufacturing analog, digital, and mixed-signal ICs for automotive, industrial, and consumer applications.

The 74VHCT series targets high-speed, low-power 5 V logic interfacing with TTL compatibility and enhanced robustness - specifically engineered for industrial control, instrumentation, and system-level bus isolation where reliability trumps raw speed.

FAQ

Can 74VHCT240AMTR safely interface 5 V and 3.3 V logic without external level shifters?

Yes. Its TTL-compatible inputs (VIH ≥ 2.0 V, VIL ≤ 0.8 V) reliably recognize 3.3 V logic highs and lows, while its outputs swing rail-to-rail (0 V to VCC) and drive both 5 V and 3.3 V CMOS loads. No external components are needed for unidirectional 5 V → 3.3 V translation, though bidirectional use requires additional isolation.

What is the maximum number of outputs that can switch simultaneously without violating noise or timing specs?

Per STMicroelectronics' dynamic switching characterization, up to seven outputs may toggle simultaneously (with one output held low) under CL = 50 pF and f = 1 MHz conditions. Exceeding this count risks violating VOLP ≤ 0.9 V and tPLH/tPHL timing margins due to ground bounce and supply droop.

Does the 74VHCT240AMTR support hot-swap insertion into a live backplane?

Yes. Its power-down protection allows all inputs and outputs to tolerate 0–7 V regardless of VCC state. When VCC = 0 V, pins remain high-impedance and non-damaging up to ±7 V - enabling safe insertion into powered systems provided current-limiting resistors are used on driven lines.

How does the 4 µA max ICC at 25°C scale across temperature and voltage?

ICC increases with temperature and VCC: at –55°C it remains ≤ 4 µA; at +125°C and VCC = 5.5 V, it rises to ≤ 40 µA per the datasheet's DC specifications table. This predictable scaling supports accurate worst-case power budgeting in wide-temperature industrial designs.