Texas Instruments SN74ALVC244NS

Overview

SN74ALVC244 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, each with separate active-low output-enable (OE) inputs, enabling bidirectional bus isolation in low-voltage digital systems such as memory address drivers and microcontroller I/O expanders.

For engineers reviewing the SN74ALVC244 datasheet, SN74ALVC244 pinout, SN74ALVC244 application, or SN74ALVC244 equivalent, key selection criteria include its 3.6-V absolute max supply rating, ±50 mA output drive capability, –40°C to 85°C industrial temperature range, and NS package thermal impedance of 100°C/W - all critical for robust signal integrity in mixed-voltage logic interfaces.

Technical Context

The SN74ALVC244 implements dual 4-bit noninverting buffers using TI's EPIC™ submicron CMOS process, supporting voltage translation between 1.8-V, 2.5-V, and 3.3-V logic domains. Its output-enable control is asynchronous and level-sensitive, with guaranteed high-impedance state during power sequencing when OE is pulled up to V_CC.

Each channel operates independently: 1A1–1A4 feed 1Y1–1Y4 under 1OE control; 2A1–2A4 feed 2Y1–2Y4 under 2OE control. Input thresholds scale with V_CC (e.g., V_IL = 0.35×V_CC at 1.65 V), and output drive strength increases with supply voltage (I_OL = 24 mA at 3 V).

Key Specifications

Pinout & Package

SN74ALVC244NS uses a 20-pin plastic small-outline (NS) package with 0.65-mm lead pitch and 100°C/W θ_JA. Pin assignments are fixed per TI SCES188: pins 1–10 and 11–20 form mirrored input/output banks with shared ground (pin 10) and V_CC (pin 20).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74ALVC244, the 74LVC244APW offers identical electrical performance in a smaller TSSOP package but requires board redesign, while SN74LVCH244A adds bus-hold inputs for improved floating-input robustness without altering timing or drive capability.

Availability

SN74ALVC244 is available at Aetrix Electronics and suitable for memory subsystems, microcontroller peripheral expansion, PCI bus isolation, and industrial sensor interface circuits requiring stable component supply across extended temperature ranges and mixed-voltage logic domains.

Supply support for SN74ALVC244 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 headquartered in Dallas, Texas, specializing in analog, embedded processing, and logic ICs for industrial, automotive, and communications markets.

The SN74ALVC244 belongs to TI's ALVC (Advanced Low-Voltage CMOS) logic family, engineered for high-speed, low-power 3-state buffering in multi-voltage digital systems where voltage translation and bus contention avoidance are critical.

FAQ

What is the maximum supply voltage rating for SN74ALVC244?

The absolute maximum supply voltage for SN74ALVC244 is 4.6 V, as specified in the Absolute Maximum Ratings table. However, recommended operation is limited to 1.65 V to 3.6 V. Exceeding 3.6 V may cause parametric degradation or reliability issues, even if below the 4.6-V stress limit. Always operate SN74ALVC244 within its recommended V_CC range for guaranteed functionality and lifetime compliance.

Does SN74ALVC244 support voltage translation between different logic families?

Yes, SN74ALVC244 supports voltage translation: its inputs accept 1.65–3.6-V signals, and outputs drive to the applied V_CC level. For example, a 1.8-V microcontroller can drive SN74ALVC244 inputs while the device outputs 3.3-V logic levels when V_CC = 3.3 V. This makes SN74ALVC244 suitable for interfacing disparate logic families without external level shifters, provided timing margins accommodate propagation delays.

How should the output-enable (OE) pins be handled during power-up?

OE pins on SN74ALVC244 must be held high (via pull-up resistor to V_CC) during power-up to ensure outputs remain in high-impedance state until system initialization completes. TI recommends a pull-up resistor value determined by the driver's current-sinking capability - typically 10 kΩ suffices for most applications. Leaving OE floating risks undefined output states and potential bus contention during power sequencing.

What is the typical propagation delay of SN74ALVC244 at 3.3 V?

The typical propagation delay (t_pd) of SN74ALVC244 is 2.8 ns at V_CC = 3.3 V, measured from input to output under CL = 50 pF load conditions. This value is confirmed in the Switching Characteristics table and applies to both A→Y and OE→Y paths. Delay remains consistent across temperature (–40°C to 85°C) and scales predictably with V_CC, dropping to 4.4 ns at 1.8 V.

Is SN74ALVC244 compatible with 5-V tolerant inputs?

No, SN74ALVC244 is not 5-V tolerant. Its absolute maximum input voltage is 4.6 V, and recommended input voltage range is 0 to V_CC. Applying 5-V signals risks permanent damage. For 5-V system interfacing, use a dedicated level translator or a 5-V-tolerant buffer such as SN74LVC8T245. SN74ALVC244 must only be used in 1.65–3.6-V environments where all connected signals stay within its VI specification.