Texas Instruments CD54HC243F3A

Overview

CD54HC243F3A from Texas Instruments is a high-speed CMOS quad-bus transceiver with three-state outputs, designed for bidirectional asynchronous communication between data buses in military-grade systems. It operates across -55°C to 125°C, supports 2 V to 6 V supply voltage, delivers 7 ns typical propagation delay (VCC = 5 V, CL = 15 pF), and drives up to 15 LSTTL loads. It is used in ruggedized avionics backplane interfaces requiring bus isolation and direction control.

For engineers reviewing the CD54HC243F3A datasheet, CD54HC243F3A pinout, CD54HC243F3A application, or CD54HC243F3A equivalent, this page provides verified functional modes, temperature-rated switching characteristics, three-state timing parameters, and military-grade packaging details specific to the CDIP (J) package with SNPB finish and hermetic ceramic seal.

Technical Context

The CD54HC243F3A implements four independent noninverting bidirectional channels, each controlled by dual enable inputs (OEA and OEB) that jointly determine both data direction (A↔B) and three-state output mode. Its silicon-gate CMOS architecture ensures low power consumption while matching LSTTL speed performance.

It features buffered inputs, balanced propagation delay and transition times, and high noise immunity (NIL/NIL = 30% of VCC at 5 V). The device is specified for full military temperature range operation and exhibits defined three-state leakage (±0.5 µA at 5.5 V) and input capacitance (10 pF).

Key Specifications

Pinout & Package

Ceramic Dual In-Line Package (CDIP, J-14), 19.55 mm × 6.71 mm body size, hermetically sealed with glass-frit lid, SNPB lead finish, no MSL rating (N/A for package type), intended for through-hole mounting in high-reliability assemblies.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CD74HC243E and CD54HCT243F, the CD54HC243F3A uniquely combines QML-38535 Class B qualification, hermetic ceramic packaging, and full 2–6 V operation-making it the only option for space-qualified or safety-critical embedded systems demanding proven reliability under extreme environmental stress.

Availability

CD54HC243F3A is available at Aetrix Electronics and suitable for avionics data bus interfaces, secure military communication backplanes, ruggedized industrial PLC I/O expansion, and satellite onboard data handling subsystems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for CD54HC243F3A 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 company specializing in analog and embedded processing solutions, with leadership in high-reliability, military-qualified logic and interface products.

The CD54HC243F3A belongs to TI's CDx4HC243 military logic family, engineered specifically for high-integrity bidirectional bus communication in defense, aerospace, and industrial systems where extended temperature operation and hermetic packaging are mandatory.

FAQ

What is the maximum propagation delay of CD54HC243F3A over its full operating temperature range?

The maximum propagation delay (t_pd) of CD54HC243F3A is 27 ns at VCC = 4.5 V and CL = 50 pF across the -55°C to +125°C range. At VCC = 6 V, the max delay is 23 ns under the same conditions. These values are measured from input transition to valid output transition and are critical for worst-case timing analysis in synchronous bus designs.

Does CD54HC243F3A support 3.3 V logic systems?

Yes, CD54HC243F3A fully supports 3.3 V operation: its HC-family specification guarantees reliable function from 2 V to 6 V, including VIH = 2.31 V (min) and VIL = 1.65 V (max) at VCC = 3.3 V. This allows direct interfacing with 3.3 V microcontrollers and FPGAs without level translation.

How does the dual-enable (OEA/OEB) control logic work in CD54HC243F3A?

In CD54HC243F3A, OEA and OEB are active-low inputs. When OEB = L and OEA = H, data flows from A to B; when OEB = H and OEA = L, data flows from B to A; when both are H, all outputs enter high-impedance state; when both are L, the channel is disabled (outputs high-Z). This prevents bus contention during state transitions.

Is CD54HC243F3A pin-compatible with CD74HC243E?

Yes, CD54HC243F3A and CD74HC243E share identical pinout (J-14 vs N-14), function mapping, and logic behavior. However, they differ in package construction (ceramic hermetic vs plastic DIP), temperature validation scope, and lead finish (SNPB vs NIPDAU), so PCB layout compatibility does not imply full interchangeability in military applications.

What is the three-state output capacitance (C_O) of CD54HC243F3A, and why does it matter?

The three-state output capacitance (C_O) of CD54HC243F3A is 20 pF. This parameter directly impacts bus settling time when exiting high-Z mode: lower C_O reduces RC time constant with bus trace capacitance, minimizing glitches during bus arbitration in multi-master systems.