Texas Instruments SN74F240DW

Overview

SN74F240DW from Texas Instruments is an octal noninverting buffer/driver with dual 4-bit sections and independent active-low 3-state output-enable (OE) inputs, designed for memory address driving and bus interfacing. It operates at 4.5–5.5 V, delivers 64 mA low-level output current, supports 0°C to 70°C ambient, and uses a 20-pin SOIC (DW) package.

For engineers reviewing the SN74F240DW datasheet, SN74F240DW pinout, SN74F240DW application, or SN74F240DW equivalent, key selection criteria include its 3-state bus-driving capability, TTL-compatible input thresholds (VIL = 0.8 V, VIH = 2 V), propagation delays under 8 ns, high-impedance leakage limits (±50 µA), and SOIC-20 thermal and layout constraints.

Technical Context

The SN74F240DW implements two independent 4-bit noninverting buffer sections, each with dedicated active-low OE control. Its logic function enables bidirectional bus isolation: when OE is low, A→Y data passes transparently; when OE is high, outputs enter high-impedance state-critical for shared-bus contention avoidance.

It belongs to the 74F (Fast TTL) family, featuring Schottky-clamped bipolar transistor design for improved speed over standard TTL. Electrical behavior is specified across 4.5–5.5 V supply and 0°C to 70°C operating range, with guaranteed VOL ≤ 0.55 V at IOL = 64 mA and tPLH/tPHL ≤ 8 ns under 50 pF load.

Key Specifications

Pinout & Package

SN74F240DW uses a 20-pin Small-Outline Integrated Circuit (SOIC) package (DW), 2.65 mm max height, 1.27 mm lead pitch, and JEDEC MS-013 compliant outline.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74F240DW, SN74LS240N trades speed and drive for lower power and broader legacy support, while SN74ACT240DW offers superior speed and input compatibility at identical footprint-making it ideal for performance-sensitive 5 V mixed-signal upgrades.

Availability

SN74F240DW is available at Aetrix Electronics and suitable for memory address buffering, bus transceiver interface, and legacy system bus expansion requiring stable component supply and long-term obsolescence management.

Supply support for SN74F240DW 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 founded in 1930, specializing in analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.

The SN74F240DW belongs to TI's 74F Fast TTL logic family, engineered for high-speed, high-drive digital interfacing in memory and bus architectures where reliability and timing predictability are critical.

FAQ

What is the maximum clock frequency supported by SN74F240DW?

The SN74F240DW does not operate on a clock signal-it is a combinatorial buffer with no internal clock. Its usable data rate depends on propagation delay (≤8 ns) and system setup/hold timing. In practice, it supports reliable operation in address/data paths up to ~12 MHz in synchronous systems with adequate margin, assuming proper PCB layout and loading.

Is SN74F240DW pin-compatible with SN74LS240?

Yes, SN74F240DW and SN74LS240 share identical pinouts (20-pin SOIC or PDIP) and logic functionality-both feature dual 4-bit noninverting buffers with independent active-low OE inputs. However, SN74F240DW has higher drive strength and faster propagation, so substitution requires verifying timing margins and load conditions in the target circuit.

Does SN74F240DW support hot-swap or live-insertion?

No, SN74F240DW is not designed for hot-swap operation. Its absolute maximum ratings do not guarantee safe biasing during partial power-up, and the absence of power-on reset or Ioff protection means uncontrolled output states may occur if VCC is applied while inputs are active. Use only in systems with controlled power sequencing.

What is the meaning of "F240" marking on the SN74F240DW package?

The top-side marking "F240" on the SN74F240DW is the abbreviated device identifier used by Texas Instruments for traceability and visual identification. It corresponds directly to the full part number SN74F240DW and confirms the device is the Fast TTL octal buffer variant in SOIC-20 packaging, as documented in TI's SDFS061A datasheet.

Can SN74F240DW drive LED displays directly?

SN74F240DW can drive common-anode LED segments at low duty cycles due to its 64 mA sink capability per output, but continuous DC drive is not recommended. Sustained 64 mA exceeds typical LED ratings (usually 20–30 mA), risking thermal overstress and accelerated degradation. For LED multiplexing, use external current-limiting resistors and verify average current remains ≤20 mA per segment.