Texas Instruments CD74HC243M96

Overview

CD74HC243M96 from Texas Instruments is a high-speed CMOS quad-bus transceiver with three-state outputs, designed for bidirectional asynchronous data bus communication between A- and B-side ports. It operates from 2 V to 6 V, delivers 7 ns typical propagation delay (VCC = 5 V, CL = 15 pF), supports -55°C to +125°C temperature range, and drives up to 15 LSTTL loads - enabling robust interface bridging in industrial control backplanes and legacy bus extender designs.

For engineers reviewing the CD74HC243M96 datasheet, CD74HC243M96 pinout, CD74HC243M96 application, or CD74HC243M96 equivalent, key selection criteria include its dual-directional 3-state control via OEA/OEB inputs, HC-series voltage flexibility, guaranteed bus-driving capability across military-grade temperature extremes, and SOIC-14 packaging compatible with automated SMT assembly.

Technical Context

The CD74HC243M96 implements four independent noninverting bidirectional buffer channels, each controlled by shared OEA and OEB enable inputs that jointly determine both direction (A→B or B→A) and high-impedance state. Its silicon-gate CMOS architecture ensures low static current (ICC ≤ 160 µA at 6 V) and high noise immunity (NIL/NIH = 30% of VCC at 5 V).

Switching behavior is characterized by balanced tPLH/tPHL propagation delays, matched output transition times (tt ≤ 15 ns at 6 V), and defined three-state timing (tPZL/tPHZ ≤ 38 ns at 6 V). Input capacitance is 10 pF; three-state output capacitance is 20 pF; power dissipation capacitance is 80 pF - all specified over full operating temperature range.

Key Specifications

Pinout & Package

CD74HC243M96 is housed in a 14-pin SOIC (D) package measuring 8.65 mm × 3.90 mm × 1.75 mm max height, with gull-wing leads, NIPDAU/SN lead finish, and JEDEC MS-012 AB-compliant outline. It is rated MSL Level-1 (unlimited floor life) and compatible with standard reflow profiles (peak 260°C).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HC243DR and CD74HCT243M96, CD74HC243M96 provides optimal balance of voltage range adaptability, speed, and legacy support - making it the default choice for mixed-supply systems where future-proofing and thermal resilience outweigh pure TTL compatibility needs.

Availability

CD74HC243M96 is available at Aetrix Electronics and suitable for industrial backplane interfaces, legacy system bus extenders, military data link buffers, and automotive ECU diagnostic ports requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for CD74HC243M96 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 logic solutions with over 50 years of high-reliability component development.

CD74HC243M96 belongs to TI's CDx4HC243 logic family, engineered for robust bidirectional bus interfacing in harsh-environment systems where wide voltage operation, precise timing control, and guaranteed three-state behavior are mandatory.

FAQ

What is the maximum clock frequency supported by CD74HC243M96 in a data bus application?

The CD74HC243M96 does not operate on a clock; it is a combinatorial bus transceiver. Its usable data rate depends on propagation delay and system timing margins. With 23 ns maximum tpd over temperature, it supports reliable operation up to approximately 20 MHz in well-terminated 50 pF bus loads - verified per TI's switching characteristics table at VCC = 6 V and TA = -55°C to +125°C.

Can CD74HC243M96 interface directly between 3.3 V and 5 V buses?

Yes, CD74HC243M96 can safely interface 3.3 V and 5 V buses when powered at 5 V. Its HC-family inputs accept VIH ≥ 3.15 V (at VCC = 5 V), which is met by 3.3 V logic high levels, and its outputs swing rail-to-rail (VOH ≥ 4.4 V, VOL ≤ 0.1 V), satisfying 5 V TTL input thresholds. No external level shifters are required in this configuration.

What happens if both OEA and OEB are driven low simultaneously on CD74HC243M96?

When both OEA and OEB are low, CD74HC243M96 enters an undefined state per TI's truth table: An and Bn become simultaneously active outputs, risking bus contention and excessive current draw. This condition violates recommended operation and must be avoided in hardware design - proper sequencing or logic gating is required to ensure only one enable is asserted at a time.

Is CD74HC243M96 pin-compatible with CD74HCT243M96?

Yes, CD74HC243M96 and CD74HCT243M96 share identical SOIC-14 pinouts, package dimensions, and terminal functions. However, they differ electrically: CD74HC243M96 accepts 2–6 V supply and CMOS-level inputs, while CD74HCT243M96 requires 4.5–5.5 V and is optimized for TTL input compatibility - substitution requires verification of voltage and interface logic levels.

Does CD74HC243M96 require external pull-up or pull-down resistors on unused pins?

Yes, all unused inputs on CD74HC243M96 - including unconnected A/B port pins and floating OEA/OEB - must be terminated to VCC or GND via 10 kΩ–1 MΩ resistors. TI explicitly warns that floating inputs cause undefined states, increased ICC, and potential oscillation due to CMOS input stage sensitivity - this is mandatory per Section 9.1 Layout Guidelines.