Texas Instruments CD74FCT623M

Overview

CD74FCT623M from Texas Instruments is a BiCMOS octal bus transceiver with noninverting 3-state bidirectional operation, 64-mA sink current capability, 3.7-V output voltage swing limit, and operation over 0°C to 70°C. It enables controlled A↔B data routing in industrial backplane and memory interface systems.

For engineers reviewing the CD74FCT623M datasheet, CD74FCT623M pinout, CD74FCT623M application, or CD74FCT623M equivalent, key selection criteria include its dual OE control for data hold, EMI-reducing output swing, BiCMOS latch-up immunity, and SOIC-20 thermal performance (θ_JA = 58°C/W).

Technical Context

The CD74FCT623M implements a BiCMOS output stage that clamps high-level output to V_CC – 1.3 V (≈3.7 V at 5 V), reducing power-bus ringing and ground bounce during simultaneous switching. Its dual output-enable inputs (OEAB, OEBA) support four functional states: A→B, B→A, isolation, and concurrent bidirectional latching.

Input/IO isolation from V_CC, buffered inputs, and controlled edge rates ensure stable timing in mixed-signal environments. The device meets FCT logic family voltage thresholds (V_IL = 0.8 V, V_VIH = 2 V) and supports TTL-compatible drive while maintaining CMOS quiescent power efficiency.

Key Specifications

Pinout & Package

CD74FCT623M is housed in a 20-pin SOIC (DW) package with 1.27-mm pitch, 7.5-mm body width, and 2.65-mm max height - compatible with standard automated assembly and IPC-7351 land patterns.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74FCT623N and 74ACT623SC, CD74FCT623M uniquely balances high-drive capability (64 mA), EMI-suppressing 3.7-V swing, and SOIC-20 thermal efficiency - making it optimal for space-constrained industrial bus interfaces requiring simultaneous switching integrity.

Availability

CD74FCT623M is available at Aetrix Electronics and suitable for industrial backplane interfaces, memory expansion subsystems, and legacy bus extender designs requiring stable component supply and long-term lifecycle support.

Supply support for CD74FCT623M 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 CD74FCT623M belongs to TI's FCT logic family - engineered for high-speed, low-noise 5-V bus interfacing in mission-critical industrial control and instrumentation systems.

FAQ

What is the maximum operating temperature range for the CD74FCT623M?

The CD74FCT623M is characterized for operation from 0°C to 70°C ambient temperature. This range is validated across all electrical parameters including propagation delay, output drive strength, and input threshold stability. The SOIC-20 package's 58°C/W thermal resistance ensures reliable performance at the upper limit when mounted on standard FR-4 PCBs with typical copper pour. CD74FCT623M remains fully compliant within this range without derating.

Does the CD74FCT623M support true bidirectional data flow without external control logic?

Yes, the CD74FCT623M supports true bidirectional data flow using only its two dedicated output-enable inputs (OEAB and OEBA). When OEAB is low and OEBA is high, data flows from A to B; when OEAB is high and OEBA is low, data flows from B to A. Simultaneous low on both enables concurrent bidirectional latching - eliminating need for external direction-control logic or clocked registers in bus-hold applications.

How does the CD74FCT623M reduce electromagnetic interference compared to standard 5-V logic transceivers?

The CD74FCT623M reduces EMI by limiting its output high-level voltage to ≈3.7 V (V_CC – 1.3 V) via BiCMOS clamping. This lowers dV/dt during switching, directly suppressing power-bus ringing and ground bounce - primary sources of radiated emissions. Measured noise characteristics show dynamic VOL(P) ≤1 V and VOH(V) ≥0.5 V under 50-pF load, confirming reduced edge-induced spectral energy. CD74FCT623M achieves this without sacrificing 64-mA drive capability.

Can the CD74FCT623M be used in systems with mixed 3.3-V and 5-V domains?

No - the CD74FCT623M is strictly a 5-V device with V_CC specified from 4.75 V to 5.25 V and input thresholds (V_IL = 0.8 V, V_VIH = 2 V) aligned to TTL levels. Its outputs swing 0 V to 3.7 V, which may not meet 3.3-V VIH minimums reliably. For mixed-voltage systems, level translators like TXB0108 or discrete resistor-divider networks are required upstream/downstream of CD74FCT623M.

What is the recommended termination for unused inputs on the CD74FCT623M?

All unused inputs on the CD74FCT623M must be tied to either V_CC or GND to prevent floating nodes that cause increased ICC, logic instability, or ESD susceptibility. TI's application report SCBA004 confirms this requirement. Pull-up or pull-down resistors of 10 kΩ to 100 kΩ are acceptable; direct connection is preferred for lowest noise. This applies to OEAB, OEBA, and any unconnected A/B bus pins - ensuring predictable behavior and meeting recommended operating conditions for CD74FCT623M.