Texas Instruments SN74F623DWR

Overview

SN74F623DWR from Texas Instruments is an octal bus transceiver with 3-state outputs, designed for asynchronous bidirectional data transfer between two 8-bit buses (A↔B). It features dual output-enable inputs (OEAB/OEBA), noninverting logic, and operates over 0°C to 70°C at 4.5–5.5 V supply. Used in legacy industrial control backplanes and TTL-based system interconnects.

For engineers reviewing the SN74F623DWR datasheet, SN74F623DWR pinout, SN74F623DWR application, or SN74F623DWR equivalent, key selection considerations include its dual-enable bus-latch capability, asymmetric drive strength (A-side: 24 mA / B-side: 64 mA low-level output), 3-state isolation timing (tPZH up to 12 ns), and SOIC-20 package compatibility with legacy 5 V TTL systems.

Technical Context

This device implements a dual-bus transceiver architecture with independent directional control via OEAB (A→B enable) and OEBA (B→A enable). Its dual-enable mode allows simultaneous activation to latch data on both buses - each output reinforces its input when both enables are active and external drivers are high-impedance.

It uses standard F-series TTL circuitry with Schottky-clamped inputs and outputs. Timing parameters are specified across 4.5–5.5 V and 0°C–70°C, with propagation delays (tPLH/tPHL) under 6.5 ns and 3-state transition times (tPZH/tPLZ) under 12 ns into 50 pF loads.

Key Specifications

Pinout & Package

SN74F623DWR is housed in a 20-pin SOIC (DW) package with 1.27 mm pitch, 2.65 mm max height, and standard JEDEC MS-013 outline. Pin 1 is marked by a beveled corner or notch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74F623DWR, SN74F245N offers simpler control but no native bus-latch capability, while 74ACT245SCX provides superior power efficiency and noise rejection at the cost of stricter input voltage compliance - both require layout or logic redesign to replace SN74F623DWR's dual-enable latching behavior.

Availability

SN74F623DWR is available at Aetrix Electronics and suitable for legacy industrial control, military avionics retrofit, and automated test equipment requiring stable component supply amid obsolescence challenges.

Supply support for SN74F623DWR 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 U.S.-based semiconductor company founded in 1930, specializing in analog, embedded processing, and logic solutions with broad industrial and aerospace heritage.

The SN74F623DWR belongs to TI's 74F TTL logic family, engineered for high-speed, robust 5 V digital interconnect in mission-critical and long-lifecycle systems where reliability and timing predictability are paramount.

FAQ

What is the function of OEAB and OEBA on the SN74F623DWR?

The SN74F623DWR uses OEAB (pin 1) to enable data flow from A bus to B bus, and OEBA (pin 19) to enable flow from B bus to A bus. When both are low, data passes bidirectionally; when both are high, all outputs enter high-impedance state. Simultaneous low enables create a bus-latch mode where outputs reinforce their inputs - a unique feature of the SN74F623DWR not found in standard octal transceivers like the 74F245.

Is SN74F623DWR still in production, and what is its status?

No - SN74F623DWR is officially obsolete per Texas Instruments' packaging addendum (OBSOLETE status as of April 2013). However, Aetrix Electronics maintains verified legacy inventory with full traceability and extended lifecycle support, including batch documentation and electrical test reports for each SN74F623DWR unit supplied.

Can SN74F623DWR operate at 3.3 V?

No - SN74F623DWR is a 5 V-only TTL device with minimum VCC of 4.5 V and VIH threshold of 2.0 V. It lacks 3.3 V tolerance; applying 3.3 V will result in undefined logic states and insufficient noise margin. For 3.3 V systems, consider logic-level translators or ACT/ALVC series alternatives - the SN74F623DWR requires strict 5 V operation.

What is the maximum capacitive load the SN74F623DWR can drive reliably?

The SN74F623DWR is characterized for CL = 50 pF in its switching specifications, with propagation delays and 3-state timing guaranteed under that load. While it may drive higher capacitance in practice, signal integrity degrades beyond 50 pF - rise/fall times increase and skew accumulates. For >50 pF traces or fanout >10, use a dedicated buffer or reduce trace length to maintain timing margins defined for the SN74F623DWR.

Does SN74F623DWR support hot-swap or live-insertion?

SN74F623DWR has no built-in hot-swap protection. Its absolute maximum ratings permit –0.5 V to 5.5 V on outputs in disabled state, but uncontrolled insertion can cause bus contention or ground bounce. Safe hot-swap requires external current-limiting resistors, slew-rate control, and sequenced enable signals - design practices must be applied externally, as the SN74F623DWR itself does not implement hot-swap logic or protection circuitry.