Texas Instruments SN74LVCH244APWRE4

Overview

SN74LVCH244APWRE4 from Texas Instruments is an octal buffer/line driver with 3-state outputs, designed for 1.65-V to 3.6-V V_CC operation. It features two independent 4-bit channels, bus-hold circuitry eliminating external pull resistors, I_off support for partial-power-down mode, and mixed-mode signal compatibility (5-V input tolerance with 3.3-V V_CC). It is used in bidirectional data buffering between 3.3-V and 5-V logic domains in industrial control backplanes.

For engineers reviewing the SN74LVCH244APWRE4 datasheet, SN74LVCH244APWRE4 pinout, SN74LVCH244APWRE4 application, or SN74LVCH244APWRE4 equivalent, key selection criteria include 3-state output timing (t_pd = 5.9 ns at 3.3 V), bus-hold current (±75 µA at 3 V), I_off leakage (<±10 µA), supply voltage range (1.65–3.6 V), and TSSOP-20 package thermal resistance (θ_JA = 83°C/W).

Technical Context

The SN74LVCH244APWRE4 implements dual 4-bit noninverting buffers with separate active-low output-enable (OE) controls per group. Each channel passes A-inputs to Y-outputs when its OE is low; outputs enter high-impedance state when OE is high. Bus-hold circuitry actively maintains undriven inputs at valid logic levels without external components.

It supports mixed-voltage translation: inputs tolerate up to 5.5 V regardless of V_CC, enabling direct interfacing between 5-V legacy peripherals and 3.3-V microcontrollers. I_off protection disables outputs during power-down to prevent back-current flow, critical for hot-swap and partial-power-down systems.

Key Specifications

Pinout & Package

TSSOP-20 (PW) package: 6.5 mm × 4.4 mm body, 0.65 mm lead pitch, 1.2 mm max height, exposed thermal pad optional for enhanced dissipation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC244APWR and 74ALVC244MTCX, the SN74LVCH244APWRE4 uniquely combines 5-V-tolerant inputs, integrated bus-hold, and I_off protection-making it the only choice for mixed-voltage, hot-swap-capable, and floating-input industrial backplane designs.

Availability

SN74LVCH244APWRE4 is available at Aetrix Electronics and suitable for industrial automation backplanes, automotive body control modules, FPGA I/O expansion, and automated test equipment requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for SN74LVCH244APWRE4 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

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and connectivity technologies, with decades of experience in high-reliability logic and interface solutions.

The SN74LVCH244A product line delivers robust, low-voltage octal buffers optimized for mixed-signal industrial, automotive, and computing systems requiring level translation, bus isolation, and partial-power-down resilience.

FAQ

What is the maximum input voltage rating for SN74LVCH244APWRE4?

The SN74LVCH244APWRE4 supports input voltages from –0.5 V to 5.5 V, independent of V_CC. This 5-V tolerance allows direct connection to legacy 5-V TTL or CMOS outputs even when powered from a 1.8-V or 3.3-V supply, eliminating external level-shifting components in mixed-voltage systems.

Does SN74LVCH244APWRE4 require external pullup or pulldown resistors on its inputs?

No. The SN74LVCH244APWRE4 integrates active bus-hold circuitry on all data inputs (1A1–1A4, 2A1–2A4), which maintains undriven or floating inputs at valid logic-high or logic-low states. Using external pull resistors with bus-hold is not recommended, as it may cause excessive current draw or logic instability.

How does SN74LVCH244APWRE4 behave during power-down sequences?

When V_CC is removed, the SN74LVCH244APWRE4's I_off circuitry disables all outputs, limiting leakage current to <±10 µA. This prevents back-current flow from live system buses into the unpowered device, protecting upstream drivers and ensuring safe partial-power-down operation in modular or hot-swap architectures.

What is the propagation delay of SN74LVCH244APWRE4 at 3.3-V operation?

At V_CC = 3.3 V and T_A = 25°C, the SN74LVCH244APWRE4 exhibits a maximum propagation delay (t_pd) of 5.9 ns from input (A) to output (Y). This value is guaranteed across the full operating temperature range (–40°C to 85°C) and ensures tight timing margins in high-speed digital interfaces such as memory expansion buses.

Can SN74LVCH244APWRE4 be used in place of SN74LVC244APWR?

SN74LVCH244APWRE4 can replace SN74LVC244APWR in most applications, but adds bus-hold functionality and retains 5-V input tolerance. If the design relies on external pull resistors or operates exclusively within a single voltage domain, SN74LVC244APWR may be sufficient. However, for floating-input or mixed-voltage use cases, SN74LVCH244APWRE4 provides superior robustness without layout changes.