Toshiba Semiconductor and Storage 74LCX244FT

Overview

74LCX244FT from Toshiba is a high-performance CMOS octal non-inverting 3-state buffer with dual active-low output enables, designed for 3.3 V system bus interfacing while supporting 5 V tolerant inputs and outputs. It delivers 6.5 ns max propagation delay at VCC = 3.0–3.6 V, ±24 mA output drive, and operates across 1.65–3.6 V supply range. It is used in memory address driver circuits and low-voltage backplane interfaces.

For engineers reviewing the 74LCX244FT datasheet, 74LCX244FT pinout, 74LCX244FT application, or 74LCX244FT equivalent, key selection criteria include 5 V tolerance on I/O pins, TSSOP20B package compatibility, 3-state timing (enable/disable skew ≤1.0 ns), and DC/AC performance under industrial temperature (−40 to +85 °C).

Technical Context

The 74LCX244FT implements two independent 4-bit non-inverting buffer groups, each controlled by its own active-low output enable (OE1̅, OE2̅). Its input and output structures incorporate protection diodes enabling safe operation up to 6.5 V, allowing direct connection to 5 V logic without level shifters.

All eight outputs support high-impedance (Z) state during disable, with guaranteed OFF-state leakage ≤±5.0 µA and power-down protection on all pins. The device meets JEDEC-standard AC/DC electrical behavior for 74LVC/ALVC-compatible 244-type logic, including defined VIH/VIL thresholds and VOL/VOH margins across VCC = 1.65–3.6 V.

Key Specifications

Pinout & Package

TSSOP20B package: 20-pin thin shrink small outline, 4.4 mm × 6.5 mm body, 0.65 mm lead pitch, exposed pad not present, RoHS-compliant matte tin lead finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 74LCX244FT, the 74LVC244APW offers faster speed but lacks 5 V tolerance-requiring redesign for mixed-voltage use-while the SN74LVCH244AQPWRQ1 adds automotive qualification and robustness at the cost of higher static current and no performance gain in standard industrial use.

Availability

74LCX244FT is available at Aetrix Electronics and suitable for industrial PLC backplanes, memory address buffering, low-power communication hubs, and test equipment signal conditioning requiring stable component supply and long-term lifecycle support.

Supply support for 74LCX244FT 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

Toshiba Electronic Devices & Storage Corporation designs and manufactures high-reliability semiconductor solutions for industrial, automotive, and consumer applications, with deep expertise in logic, power, and analog ICs.

The 74LCX series targets low-voltage, high-speed bus interface applications in 3.3 V systems requiring 5 V tolerance and JEDEC-compatible logic behavior-optimized for memory expansion, backplane interconnect, and mixed-voltage embedded control.

FAQ

What is the maximum supply voltage rating for the 74LCX244FT?

The 74LCX244FT has an absolute maximum supply voltage (VCC) rating of −0.5 V to +6.5 V, but its functional operating range is specified from 1.65 V to 3.6 V. Operation outside 1.65–3.6 V may result in undefined logic states or degraded timing, even if within absolute limits. Always operate the 74LCX244FT within its recommended VCC range for guaranteed performance.

Does the 74LCX244FT support true 5 V tolerant inputs and outputs?

Yes-the 74LCX244FT supports input and output voltages from −0.5 V to +6.5 V regardless of VCC, enabling direct connection to 5 V logic families without external level shifters. This tolerance is verified across the full operating temperature range (−40 to +85 °C) and applies to both driven and floating (3-state) pins.

What is the pin configuration for the 74LCX244FT's output enable controls?

The 74LCX244FT uses two active-low output enables: OE1̅ (pin 1) controls outputs Y1–Y4 (pins 2–5, 14–17), and OE2̅ (pin 19) controls outputs Y5–Y8 (pins 6–9, 10–13). Both enables must be low for corresponding outputs to drive; either high places its group in high-impedance state. This allows independent gating of two 4-bit bus segments.

How does the 74LCX244FT handle unused inputs?

Unused inputs on the 74LCX244FT must be tied to a valid logic level-either VCC or GND-to prevent floating nodes that could cause excessive current draw, oscillation, or ESD susceptibility. The device does not include internal pull-ups or pull-downs; external termination is required. This requirement is explicitly stated in the operating ranges section of the 74LCX244FT datasheet.

Is the 74LCX244FT pin-compatible with standard 74-series 244 devices?

The 74LCX244FT is functionally and pin-compatible with industry-standard 74LVC244, 74ALVC244, and 74F244 devices in TSSOP20 packages-including identical pin assignments for VCC, GND, OE, inputs, and outputs. However, it differs in voltage tolerance (5 V vs. 3.6 V max) and DC/AC specifications, so electrical validation is required before drop-in replacement.