Texas Instruments SN74LVCH244DW

Overview

SN74LVCH244DW from Texas Instruments is an octal buffer/driver with 3-state outputs, designed for 1.65 V to 3.6 V operation. It features two independent 4-bit channels, bus-hold circuitry on all inputs, Ioff partial-power-down support, and 5.5 V-tolerant inputs-enabling mixed-voltage interfacing in industrial control backplanes and FPGA I/O expansion systems.

For engineers reviewing the SN74LVCH244DW datasheet, SN74LVCH244DW pinout, SN74LVCH244DW application, or SN74LVCH244DW equivalent, key selection criteria include 3.3-V/5-V mixed-mode signal translation capability, sub-6 ns propagation delay at 3.3 V, high-impedance output control via dual OE inputs, and SOIC-20 package compatibility with legacy PCB layouts.

Technical Context

This device implements noninverting 3-state buffers organized as two independent 4-bit groups (A1–A4/Y1–Y4 and A1'–A4'/Y1'–Y4'), each controlled by its own output-enable (OE) input. The bus-hold circuitry actively maintains valid logic states on unused inputs without external resistors, eliminating floating node risks in high-density digital systems.

Its Ioff specification ensures that outputs are disabled and leakage current remains below ±10 µA when VCC = 0 V, preventing backflow during power sequencing. Input voltage tolerance up to 5.5 V allows direct connection to 5-V logic while operating from a 3.3-V or lower supply-critical for voltage-level bridging in heterogeneous digital subsystems.

Key Specifications

Pinout & Package

SN74LVCH244DW uses a 20-pin SOIC (DW) package measuring 12.8 mm × 7.5 mm × 2.35 mm (JEDEC MS-013), with standard 1.27 mm pitch and gull-wing leads. Pin 1 is marked by a beveled corner or dot.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC244APW and SN74LVTH244ADW, SN74LVCH244DW uniquely combines bus-hold, Ioff, and 5.5-V input tolerance in a single SOIC-20 package-making it optimal for mixed-voltage, hot-swap, and space-constrained industrial upgrades.

Availability

SN74LVCH244DW is available at Aetrix Electronics and suitable for industrial automation backplanes, FPGA I/O expansion modules, memory subsystems, and legacy system upgrades requiring stable component supply and long-term manufacturability.

Supply support for SN74LVCH244DW 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 logic solutions for industrial, automotive, and communications markets.

The SN74LVCH244DW belongs to TI's LVCH logic family, engineered specifically for robust mixed-voltage interfacing in harsh industrial environments where reliability, power sequencing safety, and PCB real estate efficiency are critical.

FAQ

What is the maximum operating frequency supported by SN74LVCH244DW?

The SN74LVCH244DW does not specify a maximum clock frequency, but its 5.9 ns typical propagation delay at 3.3 V enables reliable operation in data paths up to approximately 100 MHz with adequate timing margin. Actual usable frequency depends on load capacitance, trace length, and system-level timing constraints-notably setup/hold times of driven devices. For synchronous bus applications, designers should verify timing closure using worst-case tpd and tdis values from the datasheet.

Can SN74LVCH244DW be used to translate 5-V signals to a 1.8-V microcontroller?

Yes, SN74LVCH244DW accepts 5-V inputs while operating from a 1.8-V VCC, making it suitable for translating 5-V signals down to 1.8-V logic levels. Its outputs will swing between 0 V and ~1.6 V (VOL ≈ 0.45 V, VOH ≈ 1.6 V at VCC = 1.8 V), which meets 1.8-V CMOS input thresholds. However, ensure the receiving microcontroller's VIH(min) ≤ 1.6 V and VIL(max) ≥ 0.45 V-verify compatibility using the specific MCU's datasheet.

Does SN74LVCH244DW require external pull-up resistors on its inputs?

No, SN74LVCH244DW includes active bus-hold circuitry on all eight data inputs, which maintains a valid logic state without external pull-up or pull-down resistors. Using external resistors with bus-hold enabled is not recommended, as they may conflict with the internal hold current and degrade noise immunity. This feature reduces BOM count and simplifies layout in high-density digital systems.

How does the Ioff feature of SN74LVCH244DW protect the system during power-down?

The Ioff feature in SN74LVCH244DW disables output drivers and limits leakage current to ±10 µA when VCC = 0 V, preventing damaging current backflow through the device from powered sections of the system. This protects both the SN74LVCH244DW and upstream/downstream components during hot-swap events, partial power-down, or mismatched power sequencing-ensuring robust operation in modular backplane architectures.

Is SN74LVCH244DW pin-compatible with older 74-series buffers like SN74LS244?

No, SN74LVCH244DW is not pin-compatible with SN74LS244. While both are octal 3-state buffers in 20-pin packages, their pinouts differ significantly: SN74LS244 uses dual OE inputs on pins 1 and 19, whereas SN74LVCH244DW places 1OE on pin 1 and 2OE on pin 19 but assigns different A/Y signal mappings and power/ground locations. PCB layout reuse requires verification against the DW package top-view diagram in the SN74LVCH244A datasheet.