Texas Instruments SN74LV244APWG4

Overview

SN74LV244APWG4 from Texas Instruments is an octal 3-state buffer/driver IC designed for bidirectional signal buffering in bus-oriented systems. It features dual 4-bit groups with independent output-enable (OE) controls, operates from 2 V to 5.5 V, delivers ≤6.5 ns propagation delay at 5 V, supports mixed-mode voltage translation, and includes Ioff for partial-power-down operation. It is used in server memory address buffering and telecom backplane interface isolation.

For engineers reviewing the SN74LV244APWG4 datasheet, SN74LV244APWG4 pinout, SN74LV244APWG4 application, or SN74LV244APWG4 equivalent, key selection criteria include VCC range compatibility (2–5.5 V), 3-state timing (tpd/ten/tdis), Ioff leakage (<5 µA), thermal performance in TSSOP-20, and functional grouping of two independent 4-bit drivers.

Technical Context

The SN74LV244APWG4 implements two independent 4-bit non-inverting buffer sections, each with dedicated active-low output-enable (1OE, 2OE) inputs controlling high-impedance state entry/exit. Its balanced CMOS 3-state outputs source/sink up to ±16 mA at 4.5–5.5 V while maintaining VOL ≤ 0.55 V and VOH ≥ 3.8 V under full load.

It supports mixed-voltage interfacing across ports - e.g., 3.3-V inputs driving 5-V outputs - enabled by wide VCC tolerance and standard CMOS input thresholds. The Ioff circuitry ensures <5 µA power-off leakage when VCC = 0 V, enabling hot-swap capability without backfeeding.

Key Specifications

Pinout & Package

Packaged in a 20-pin TSSOP (PW), the SN74LV244APWG4 measures 6.50 mm × 7.8 mm with exposed leadframe for enhanced thermal dissipation. RθJA = 128.2°C/W and RθJB = 79.3°C/W support reliable operation in compact, convection-cooled PCB layouts.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal 3-state buffer applications.

Compared with SN74LVC244APW and 74LVX244M, the SN74LV244APWG4 uniquely supports 5-V operation, includes Ioff for safe partial power-down, and enables mixed-voltage interfacing - making it the only option qualified for industrial 5-V bus buffering with hot-swap capability.

Availability

SN74LV244APWG4 is available at Aetrix Electronics and suitable for server motherboard design, telecom infrastructure backplanes, and industrial motor-drive control requiring stable component supply across extended temperature and long product lifecycles.

Supply support for SN74LV244APWG4 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, with decades of expertise in high-reliability industrial and communications ICs.

The SN74LV244A belongs to TI's LV logic family, engineered for low-voltage operation (2–5.5 V), high noise immunity, and robust 3-state bus interfacing in demanding infrastructure applications.

FAQ

What is the maximum propagation delay of the SN74LV244APWG4 at 3.3 V?

The SN74LV244APWG4 has a maximum propagation delay (tpd) of 11.9 ns at VCC = 3.3 V, CL = 50 pF, and TA = –40°C to 125°C. This value is specified in the Switching Characteristics table (Section 6.9) and reflects worst-case timing under industrial temperature and load conditions. The typical tpd is 6.8 ns under the same conditions, confirming consistent high-speed performance across its operating range. SN74LV244APWG4 maintains this timing stability due to its balanced CMOS output architecture.

Does the SN74LV244APWG4 support hot-swap or partial power-down operation?

Yes, the SN74LV244APWG4 supports partial power-down via its Ioff feature, which limits input/output leakage to <5 µA when VCC = 0 V. This prevents current backflow from live buses into unpowered sections, enabling safe hot-swap in modular telecom and server systems. The SN74LV244APWG4 achieves this through internal circuitry that disables all I/O paths independently of input states - a capability confirmed in Section 8.3.3 and Electrical Characteristics Table 6.5.

What is the recommended bypass capacitor for the SN74LV244APWG4?

Texas Instruments recommends a 0.1-µF ceramic capacitor placed as close as possible between VCC (Pin 20) and GND (Pin 10) for the SN74LV244APWG4. This value is specified in Section 9.3 for single-supply devices and is critical to suppress high-frequency switching noise and maintain stable VCC during output transitions. For improved broadband decoupling, a parallel 1-µF capacitor may be added - but the 0.1-µF unit must be physically adjacent to the TSSOP package pins to minimize inductance. SN74LV244APWG4 exhibits optimal noise immunity only when this layout guideline is followed.

Can unused inputs on the SN74LV244APWG4 be left floating?

No, unused inputs on the SN74LV244APWG4 must never be left floating. As stated in Section 6.3 and Section 8.3.2, all unused CMOS inputs must be terminated to either VCC or GND to prevent undefined logic states, excessive power consumption, or oscillation. A 10-kΩ pullup or pulldown resistor is recommended if the input may transition later; direct connection is acceptable for permanently static signals. Leaving inputs unconnected violates the Absolute Maximum Ratings and risks malfunction - a requirement explicitly enforced for reliable SN74LV244APWG4 operation.

What is the maximum capacitive load the SN74LV244APWG4 can drive while meeting datasheet specifications?

The SN74LV244APWG4 is characterized and guaranteed to meet all datasheet specifications - including tpd, VOL, and VOH - with a total output load capacitance ≤50 pF, as confirmed in Section 9.2.1 and Switching Characteristics tables. While larger loads (e.g., 100 pF) may function, timing degradation, increased ground bounce, and reduced noise margins occur beyond this limit. For reliable SN74LV244APWG4 deployment in high-speed bus applications, trace length, connector parasitics, and receiver input capacitance must be summed and held at or below 50 pF per output.