onsemi 74LCX2244MSAX

Overview

74LCX2244MSAX from Fairchild Semiconductor is an octal non-inverting 3-STATE buffer/line driver designed for low-voltage (2.3V–3.6V) V_CC operation with 5V-tolerant inputs and outputs, integrated 26Ω output series resistors, 7.5 ns max propagation delay at 3.3V, and ±12 mA drive capability at 3.0V - used in memory address buffering, clock distribution, and bidirectional bus interfacing.

For engineers reviewing the 74LCX2244MSAX datasheet, pinout, applications, or equivalent options, key selection criteria include 5V tolerance across mixed-voltage systems, output impedance control for signal integrity, 3-STATE enable logic partitioning (OE1/OE2), and SSOP-20 package compatibility with high-density PCB layouts.

Technical Context

The 74LCX2244MSAX implements dual independent 3-STATE enable controls (OE1 on pins 12/14/16/18; OE2 on pins 3/5/7/9), allowing grouped output disable for bus arbitration. Its advanced CMOS process enables 2.3V–3.6V operation while maintaining 5V I/O tolerance via robust input clamping and output stage design.

Each of the eight non-inverting buffers features built-in 26Ω series resistors to suppress overshoot/undershoot in transmission-line environments. Propagation delay (t_PHL/t_PLH) remains ≤7.5 ns at V_CC = 3.3V with 50 pF load, and power-down leakage is limited to 10 µA ICC max under quiescent conditions.

Key Specifications

Pinout & Package

74LCX2244MSAX is packaged in a 20-lead Shrink Small Outline Package (SSOP), JEDEC MO-150 compliant, 5.3 mm wide, with 0.65 mm lead pitch and exposed thermal pad (non-electrical). Pin numbering follows standard SSOP convention with pin 1 marked by notch or dot.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar buffer/line driver applications.

Compared with 74LVC244APW,118 and SN74LVCH244AQPWRQ1, the 74LCX2244MSAX uniquely combines dual-group 3-STATE control, on-die 26Ω termination, and guaranteed 5V I/O tolerance - enabling simpler, more robust designs in mixed-voltage industrial backplanes.

Availability

74LCX2244MSAX is available at Aetrix Electronics and suitable for memory address buffering, low-voltage clock distribution, and hot-swappable I/O module interfaces requiring stable component supply across extended product lifecycles.

Supply support for 74LCX2244MSAX 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

Fairchild Semiconductor was a leading designer of high-performance analog and power ICs, acquired by ON Semiconductor in 2016; its logic portfolio remains widely deployed in industrial and communications infrastructure.

The 74LCX2244MSAX belongs to the LCX low-voltage CMOS logic family, engineered specifically for mixed-signal systems requiring 2.5V/3.3V core logic with seamless 5V peripheral interfacing and enhanced noise immunity.

FAQ

What voltage levels can the 74LCX2244MSAX inputs and outputs tolerate?

The 74LCX2244MSAX inputs and outputs are rated for 0V to 5.5V DC, independent of V_CC (2.3V–3.6V). This allows direct connection to 5V signals without clamping diodes or level shifters. The device maintains full functionality and specified timing across this range, making it ideal for bridging legacy 5V buses with modern low-voltage controllers. Always observe absolute maximum ratings: VI and VO must not exceed −0.5V to +7.0V.

How does the dual OE architecture of the 74LCX2244MSAX improve system design?

The 74LCX2244MSAX provides two independent 3-STATE enable inputs - OE1 controls outputs O4–O7, and OE2 controls O0–O3 - enabling segmented bus control without external logic. This simplifies arbitration in multi-master systems and reduces simultaneous switching noise by allowing staggered enable/disable sequencing. For example, a microcontroller can isolate memory upper/lower banks independently, improving signal integrity and reducing ground bounce in dense PCB layouts.

Does the 74LCX2244MSAX require external series termination resistors?

No - the 74LCX2244MSAX integrates 26Ω series resistors on all eight outputs, explicitly designed to dampen transmission-line reflections and reduce EMI in unterminated or lightly loaded traces. This eliminates the need for eight discrete 22Ω–33Ω resistors, saving board space and BOM cost. The value is optimized for typical FR-4 trace impedances (50–75Ω) and matches the AC characteristics specified in the datasheet under CL = 50 pF conditions.

What is the recommended power-up sequence for reliable 3-STATE behavior of the 74LCX2244MSAX?

To ensure outputs remain in high-impedance during power-up, OE1 and OE2 must be held HIGH before V_CC reaches 1.0V. Fairchild recommends tying each OE pin to V_CC via a pull-up resistor (value determined by driver sink capability; typically 10kΩ). Floating OE pins may cause undefined output states, risking bus contention. The 74LCX2244MSAX's power-down high-impedance feature further guarantees safe behavior during brownout or shutdown sequences.

Is the 74LCX2244MSAX suitable for automotive applications?

The 74LCX2244MSAX is not AEC-Q100 qualified and is intended for industrial and commercial applications only. While it operates over −40°C to +85°C and exhibits robust latch-up immunity (>500 mA), it lacks automotive-specific validation for temperature cycling, humidity resistance, and long-term reliability under vibration. For automotive use, consider functionally similar alternatives like SN74LVCH244AQPWRQ1, which carries full AEC-Q100 Grade 2 qualification and extended lifetime testing.