Texas Instruments SN74ALVCH244DW

Overview

SN74ALVCH244DW from Texas Instruments is an octal buffer/driver with 3-state outputs, designed for 1.65-V to 3.6-V V_CC operation. It features two independent 4-bit channels (1A–1Y and 2A–2Y), bus-hold circuitry on all data inputs, ±24-mA output drive at 3.3 V, and 2.8-ns max propagation delay. It is used in bidirectional bus interfacing between mixed-voltage logic domains in industrial control backplanes.

For engineers reviewing the SN74ALVCH244DW datasheet, SN74ALVCH244DW pinout, SN74ALVCH244DW application, or SN74ALVCH244DW equivalent, key selection criteria include 3-state enable timing (t_en = 4.5 ns, t_dis = 4.2 ns at 3.3 V), bus-hold input current (±45 µA at 2.3 V), and SOIC-20 package thermal resistance (θ_JA = 58 °C/W).

Technical Context

The SN74ALVCH244DW implements dual 4-bit noninverting buffers with separate active-low output-enable (1OE, 2OE) controls. Each channel operates independently: when its OE is low, A→Y data passes with TTL-compatible thresholds; when high, outputs enter high-impedance state. Bus-hold circuitry actively maintains valid logic levels on undriven inputs without external resistors.

It supports mixed-voltage system interfacing via 1.65–3.6-V supply tolerance and level-shifted input thresholds (e.g., V_IL = 0.35×V_CC at 1.65 V). Output drive strength scales with V_CC: ±4 mA at 1.65 V, ±24 mA at 3.0 V. Latch-up immunity exceeds 250 mA per JESD 17, and ESD protection meets 2000-V HBM and 200-V MM.

Key Specifications

Pinout & Package

SN74ALVCH244DW is housed in a 20-pin SOIC (DW) package, 7.5 mm × 12.8 mm footprint, 2.65 mm max height, RoHS-compliant NiPdAu lead finish, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74ALVCH244DW, SN74LVC244APWR lacks bus-hold and offers reduced drive below 3.3 V, increasing BOM complexity; 74AVC244BQX delivers faster timing and broader low-voltage support but requires PCB redesign for TSSOP-20 placement and thermal relief.

Availability

SN74ALVCH244DW is available at Aetrix Electronics and suitable for industrial backplane interfaces, memory expansion subsystems, FPGA I/O expansion hubs, and legacy peripheral adapters requiring stable component supply across extended temperature ranges.

Supply support for SN74ALVCH244DW 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 company specializing in analog, embedded processing, and logic ICs, with decades of leadership in interface and bus technology.

The SN74ALVCH244DW belongs to TI's ALVCH logic family, engineered for low-voltage mixed-signal systems where bus integrity, power efficiency, and interoperability across voltage domains are critical.

FAQ

What is the maximum operating temperature for SN74ALVCH244DW?

The SN74ALVCH244DW is rated for operation from –40°C to +85°C ambient temperature. Its SOIC-DW package has a θ_JA of 58 °C/W, so at 85°C ambient and 120 mW power dissipation, junction temperature remains within safe limits (T_J ≈ 155°C), well below the 150°C absolute max storage rating.

Does SN74ALVCH244DW require external pull-up resistors on its inputs?

No. The SN74ALVCH244DW integrates active bus-hold circuitry on all eight data inputs (1A1–1A4, 2A1–2A4), which maintains valid logic states without external pull-up or pull-down resistors. Using external resistors with bus-hold is explicitly discouraged in the datasheet as it may cause contention or excessive current draw.

Can SN74ALVCH244DW interface directly between 1.8-V and 3.3-V logic domains?

Yes. The SN74ALVCH244DW operates across 1.65–3.6-V V_CC, accepts input voltages up to V_CC + 0.5 V, and provides output levels compatible with both 1.8-V and 3.3-V receivers. When powered at 1.8 V, it correctly interprets 3.3-V inputs via internal clamping diodes, making it suitable for bidirectional level translation without external components.

What is the recommended power supply decoupling for SN74ALVCH244DW?

A 0.1-µF ceramic capacitor must be placed between V_CC (Pin 20) and GND (Pin 10) within 5 mm of the SN74ALVCH244DW package. For systems with high switching activity across multiple channels, add a bulk 4.7-µF tantalum capacitor near the power entry point to suppress low-frequency ripple and maintain stable V_CC under transient load conditions.

How does the output-enable timing of SN74ALVCH244DW affect bus arbitration?

The SN74ALVCH244DW specifies t_en = 4.5 ns and t_dis = 4.2 ns (at 3.3 V), ensuring rapid, predictable transitions into and out of high-impedance state. This tight timing window prevents bus contention during multi-master arbitration cycles, especially critical in shared-memory architectures where multiple devices drive the same data lines under strict OE synchronization.