onsemi 74LVTH2244SJX

Overview

74LVTH2244SJX from ON Semiconductor is a low-voltage octal buffer/line driver with 3-STATE outputs and integrated 25Ω series output resistors, designed for memory address and clock distribution in 3.3V systems interfacing to 5V TTL buses. It features bushold inputs (eliminating external pull-ups), ±12mA drive strength, and operates from 2.7V to 3.6V over –40°C to +85°C.

For engineers reviewing the 74LVTH2244SJX datasheet, pinout, applications, or equivalent options, key selection criteria include bushold input support, 25Ω output series termination, 3-STATE bus isolation timing (tPZH ≤ 7.7ns), and SOIC-20 compatibility for high-density PCB layouts.

Technical Context

The 74LVTH2244SJX implements dual 4-bit non-inverting buffers with independent 3-STATE enable controls (OE1/OE2), each driving four outputs (O0–O3 and O4–O7). Its bushold circuitry actively maintains input logic state when floating, reducing system-level component count and improving noise immunity on unterminated data lines.

Each output integrates a 25Ω series resistor to dampen signal reflections and suppress overshoot/undershoot on transmission lines - critical for clean edge integrity in high-speed bus applications. The device uses advanced BiCMOS technology to achieve ABT-class speed (tPLH/tPHL ≤ 5.3ns) while maintaining LVT-class power efficiency (ICCZ ≤ 0.19mA).

Key Specifications

Pinout & Package

74LVTH2244SJX is housed in a 20-lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm wide (Package Code M20D), with standard SOIC footprint compatibility and gull-wing leads.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 74LVTH2244SJX, the 74LVT2244SJX lacks bushold and increases BOM count, while the SN74LVC244APWR omits both 5V tolerance and output resistors - making 74LVTH2244SJX uniquely suited for mixed-voltage, high-integrity bus interfaces requiring minimal external components.

Availability

74LVTH2244SJX is available at Aetrix Electronics and suitable for memory address buffering, clock distribution, backplane bus interfacing, and industrial I/O expansion requiring stable component supply and long-term industrial lifecycle support.

Supply support for 74LVTH2244SJX 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

ON Semiconductor (formerly Fairchild Semiconductor) is a global leader in intelligent power and sensing solutions, serving automotive, industrial, cloud, and consumer markets with energy-efficient semiconductor technologies.

The 74LVTH2244SJX belongs to ON Semiconductor's legacy LVT/LVTH logic family, engineered specifically for high-speed, low-voltage bus interfacing with robust noise immunity and mixed-voltage compatibility in industrial and computing infrastructure.

FAQ

What is the function of the bushold feature in the 74LVTH2244SJX?

The bushold feature in the 74LVTH2244SJX actively retains the last valid logic state on each input pin when left unconnected or floating - eliminating the need for external pull-up or pull-down resistors. This reduces component count, improves noise immunity on unterminated lines, and prevents undefined behavior during power-up or signal glitches. The 74LVTH2244SJX implements this via internal feedback circuitry on all eight inputs, distinguishing it from the non-bushold 74LVT2244SJX variant.

Does the 74LVTH2244SJX support 5V-tolerant inputs?

Yes, the 74LVTH2244SJX supports 5V-tolerant inputs: its VI rating extends to 5.5V under recommended operating conditions, enabling direct connection to 5V TTL signal sources while powered from a 3.3V supply. This allows seamless interfacing between legacy 5V logic and modern 3.3V systems without level shifters. However, outputs are not 5V-tolerant in HIGH state - they swing to VCC – 0.2V (≈3.1V), so external pull-ups may be needed for true 5V logic-high recognition by downstream 5V receivers.

What is the purpose of the 25Ω series resistors on the outputs of the 74LVTH2244SJX?

The 25Ω series resistors integrated into each output of the 74LVTH2244SJX serve as source termination to dampen signal reflections on PCB traces, reducing overshoot, undershoot, and ringing - especially critical for clean signal integrity in high-speed bus applications. These resistors are fabricated monolithically and matched across all eight outputs, eliminating the need for eight discrete 25Ω resistors and saving board area. They are effective for trace lengths up to ~10 cm with typical FR-4 impedance (~50–75Ω).

How does the 74LVTH2244SJX handle power-up and power-down sequencing?

The 74LVTH2244SJX features power-up/power-down high-impedance behavior: outputs remain in 3-STATE during VCC ramp-up and ramp-down, preventing false data assertion or bus contention when supply voltage is outside the valid operating range. This is achieved through internal enable circuitry that monitors VCC and holds OE logic inactive until stable. As a result, the 74LVTH2244SJX supports glitch-free hot-plug operation and safe integration into systems with asymmetric power sequencing requirements.

What package type is used for the 74LVTH2244SJX, and is it compatible with standard SOIC footprints?

The 74LVTH2244SJX uses a 20-lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm wide (Package Code M20D), which shares identical pin pitch (1.27mm), lead count, and mechanical outline with JEDEC MS-013 SOIC-20 - enabling drop-in compatibility with standard SOIC-20 land patterns. Its gull-wing leads and 5.3mm body width meet EIAJ specifications, and it is fully RoHS-compliant and lead-free per JEDEC J-STD-020B. No PCB layout changes are required when migrating from SOIC-20 variants like 74LVTH2244WM.