Texas Instruments SN74ACT240PWG4

Overview

SN74ACT240PWG4 from Texas Instruments is an octal 3-state inverting buffer/driver IC designed for bus-oriented data transmission, clock distribution, and memory address driving in high-density digital systems. It operates at 4.5 V to 5.5 V, delivers ≤8.5 ns propagation delay at 5 V, supports TTL-compatible inputs up to 5.5 V, and features dual independent output-enable controls for flexible bus management in industrial control and telecom infrastructure.

For engineers reviewing the SN74ACT240PWG4 datasheet, SN74ACT240PWG4 pinout, SN74ACT240PWG4 application, or SN74ACT240PWG4 equivalent, this page provides verified functional mode behavior, TSSOP-20 package–specific pin mapping, switching characteristics under 5 V operation, thermal resistance (R_θJA = 126.2 °C/W), and validated alternative options for 3-state octal buffering in space-constrained designs.

Technical Context

The SN74ACT240PWG4 implements two independent 4-bit inverting buffer sections, each with dedicated output-enable (OE) inputs (1OE and 2OE). When OE is low, data passes inverted from A inputs to Y outputs; when OE is high, outputs enter high-impedance state-enabling bidirectional bus arbitration without external logic.

Its balanced CMOS push-pull outputs source/sink ±24 mA at V_CC = 4.5 V, support fast edge rates (≤8.5 ns t_PLH/t_PHL), and maintain input compatibility with both TTL and 5 V CMOS logic families. The device is rated for operation from –40 °C to +85 °C and meets RoHS compliance with NIPDAU lead finish.

Key Specifications

Pinout & Package

TSSOP-20 package (PW), 6.5 mm × 6.4 mm body size, 1.2 mm max height, RoHS-compliant NIPDAU lead finish, moisture sensitivity level 1 (260 °C peak reflow).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74ACT240PWG4, SN74ACT240PWR offers identical functionality with active production status, while SN74LVC240APWR trades 5 V compatibility for reduced size and power-making it viable only in pure 3.3 V architectures where voltage translation is acceptable.

Availability

SN74ACT240PWG4 is available at Aetrix Electronics and suitable for industrial control systems, telecom infrastructure equipment, and medical imaging hardware requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for SN74ACT240PWG4 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 over 90 years of innovation in high-reliability electronic components.

The SNx4ACT240 family was engineered for high-speed, low-noise bus interfacing in industrial and communications equipment-emphasizing robust 5 V operation, precise timing control, and seamless integration with legacy TTL and CMOS logic systems.

FAQ

What is the operating temperature range for SN74ACT240PWG4?

The SN74ACT240PWG4 is specified for industrial operation from –40 °C to +85 °C. This range is validated per TI's recommended operating conditions and applies to all electrical parameters including propagation delay, output drive, and input thresholds. The device uses standard TSSOP packaging with NIPDAU finish and meets JEDEC MSL-1 reflow requirements for surface-mount assembly across this full temperature span. SN74ACT240PWG4 performance remains stable under thermal cycling within these limits.

Does SN74ACT240PWG4 support 3.3 V logic inputs?

Yes, SN74ACT240PWG4 accepts 3.3 V logic inputs reliably: its V_IL (max) is 0.8 V and V_IH (min) is 2.0 V at V_CC = 4.5–5.5 V, providing ample margin for 3.3 V CMOS outputs. However, note that SN74ACT240PWG4 itself requires a 4.5–5.5 V supply and does not operate at 3.3 V. It functions as a level translator-accepting 3.3 V inputs while driving 5 V-compatible outputs-without external biasing.

What is the maximum output current capability of SN74ACT240PWG4?

SN74ACT240PWG4 delivers ±24 mA per output at V_CC = 4.5 V, as specified in the Recommended Operating Conditions table. This drive strength supports direct connection to 50 Ω transmission lines or up to 10 standard TTL loads. Absolute maximum ratings permit short-duration ±50 mA pulses, but sustained operation above ±24 mA risks thermal overload given the TSSOP-20 package's R_θJA of 126.2 °C/W. SN74ACT240PWG4 must be used within these limits to ensure reliability.

How does the dual OE architecture of SN74ACT240PWG4 improve system design?

The SN74ACT240PWG4 features two independent output-enable inputs (1OE and 2OE), allowing separate control of its two 4-bit buffer sections. This enables time-gated or priority-based bus access-for example, holding one data lane active while tri-stating another during arbitration. It eliminates need for external logic gates or additional drivers in systems requiring phased bus release, such as memory-mapped I/O expansion. SN74ACT240PWG4 thus reduces component count and PCB area in multi-peripheral interfaces.

Is SN74ACT240PWG4 pin-compatible with other packages in the SN74ACT240 family?

No-SN74ACT240PWG4 uses the TSSOP-20 (PW) package with 0.65 mm lead pitch and specific land pattern (6.5 mm × 6.4 mm body), differing mechanically from SOIC-20 (DW), SSOP-20 (DB), or PDIP-20 (N) variants. While all SN74ACT240 variants share identical pin functions and logic behavior, their footprints are not interchangeable. Board layout must match the PW package outline; substitution requires redesign. SN74ACT240PWG4's pin numbering follows JEDEC MO-153, confirmed in TI's PW0020A package drawing.