STMicroelectronics 74LCX244MTR

Overview

74LCX244MTR from STMicroelectronics is a low-voltage CMOS octal non-inverting 3-state bus buffer with 5V-tolerant inputs and outputs, operating from 2.0V to 3.6V supply, delivering 6.5 ns max propagation delay at VCC = 3.0V, ±24 mA output drive, and symmetrical output impedance for PCI-bus-level interfacing in 3.3V systems with 5V signal compatibility.

For engineers reviewing the 74LCX244MTR datasheet, 74LCX244MTR pinout, 74LCX244MTR application, or 74LCX244MTR equivalent, key selection criteria include 3-state enable timing (tPZL/tPLZ ≤ 8.0 ns), 5V tolerance on all I/Os, latch-up immunity >500 mA, ESD robustness (HBM >2000V), and SO-20 package compatibility with legacy 74-series layouts.

Technical Context

This device implements dual 4-bit non-inverting buffers with independent 3-state control (1G and 2G), enabling bidirectional data routing in memory address/data buses. Each buffer section supports high-speed switching with balanced tPLH ≅ tPHL and skew <1.0 ns across outputs under 50 pF load.

Input and output protection circuits ensure safe operation during power sequencing: inputs remain high-impedance and clamped during VCC = 0V (power-down protection), while outputs tolerate up to 7.0V absolute max voltage regardless of supply state - critical for mixed-voltage board-level interfacing.

Key Specifications

Pinout & Package

74LCX244MTR is housed in a 20-pin SOIC (Small Outline Integrated Circuit) package per JEDEC MS-013, 0.300-inch body width, with 1.27 mm pitch and gull-wing leads. Pin 1 marked by notch or bevel.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 74LCX244MTR, the LVC variant trades 5V tolerance for lower quiescent current, while the LVCH offers greater drive but lacks native 5V input robustness - making 74LCX244MTR uniquely suited for mixed-voltage legacy integration without redesign.

Availability

74LCX244MTR is available at Aetrix Electronics and suitable for memory address buffering, PCI bus interfacing, hot-swap backplane design, and low-power embedded data multiplexing requiring stable component supply and long-term industrial lifecycle support.

Supply support for 74LCX244MTR 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 markets.

The 74LCX logic family targets high-speed, low-voltage 3.3V system interfacing with 5V tolerance - specifically engineered for seamless migration from 5V TTL/CMOS while minimizing power and board space.

FAQ

Is 74LCX244MTR pin-compatible with standard 74LS244?

Yes - it uses identical SO-20 pinout and function mapping (1G, 1A1–1A4, 1Y1–1Y4, 2Y1–2Y4, 2A1–2A4, 2G, GND, VCC), enabling direct replacement in existing 74-series layouts. However, its 5V-tolerant I/O and 3.3V supply requirement mean VCC must be re-routed to 3.3V, and unused inputs must be terminated to avoid floating states.

What is the maximum safe input voltage when VCC = 0V?

Per Absolute Maximum Ratings, VI may reach –0.5V to +7.0V regardless of VCC state. With VCC = 0V, inputs remain protected by internal diodes clamping to GND and VCC (0V), allowing safe application of up to 5.5V signals - confirmed by power-down protection feature and 2000V HBM ESD rating.

Can 74LCX244MTR drive a 50Ω transmission line directly?

No - its 10 pF COUT and ±24 mA drive are optimized for CMOS bus loading (≤ 10–15 pF per stub), not 50Ω RF termination. For controlled-impedance traces, use series source termination (e.g., 33Ω resistor at driver output) to suppress reflections while preserving signal integrity within its 6.5 ns timing budget.

Does 74LCX244MTR support partial power-down (e.g., VCC applied but some I/Os inactive)?

Yes - all I/Os feature independent protection circuitry. When VCC is applied, unused inputs can be left open (with ≤±5 µA leakage) or tied to GND/VCC; outputs in 3-state mode exhibit only ±5 µA IOZ leakage. No external pull resistors are required for stability, though OE control must remain valid to prevent unintended bus contention.