Texas Instruments CD74HC257M96

Overview

CD74HC257M96 from Texas Instruments is a quad 2-input CMOS multiplexer with three-state non-inverting outputs, designed for data routing in digital systems. It features 12ns typical propagation delay at 5V/15pF, operates from 2V to 6V, supports -55°C to +125°C temperature range, and uses active-low Output Enable (OE) for bus isolation. It is commonly used in register-to-bus data selection and function generation circuits.

For engineers reviewing the CD74HC257M96 datasheet, CD74HC257M96 pinout, CD74HC257M96 application, or CD74HC257M96 equivalent, key selection criteria include its 16-pin SOIC package, HC logic family compatibility, three-state output control, and wide supply voltage tolerance - critical for industrial and aerospace signal routing designs.

Technical Context

The CD74HC257M96 implements four identical 2:1 multiplexers sharing one common Select (S) input and one active-low Output Enable (OE) input. Each multiplexer routes either I0 or I1 to its Y output based on S state, with all outputs entering high-impedance when OE is HIGH.

Its HC logic family ensures CMOS-level input thresholds (VIH = 1.5V min at 2V VCC; VIL = 0.5V max), 10 LSTTL fanout capability over full temperature range, and balanced propagation delays between rising/falling edges - enabling reliable timing in synchronous bus architectures.

Key Specifications

Pinout & Package

CD74HC257M96 is housed in a 16-lead SOIC (Small Outline Integrated Circuit) package with standard JEDEC MS-012AC dimensions (5.3mm width, 10.2mm length). Pin 1 is located at the top-left corner of the package, identified by a beveled edge or dot marking.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad 2-input multiplexer applications.

Compared with CD74HC257M96, SN74HC157DR offers improved propagation delay consistency and longer-term availability, while MC74HC257ADR2G provides a validated second source with minor electrical trade-offs in leakage and output drive - both retain identical 16-pin SOIC footprint and functional behavior.

Availability

CD74HC257M96 is available at Aetrix Electronics and suitable for industrial PLC I/O expansion, aerospace avionics data routing, and test equipment signal switching requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for CD74HC257M96 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 ICs, with decades of heritage in high-reliability logic families.

The CD74HC257M96 belongs to TI's CD74HC high-speed CMOS logic series, engineered for robust performance in harsh-environment digital systems where wide voltage operation, noise immunity, and extended temperature stability are mandatory.

FAQ

What is the maximum operating frequency supported by CD74HC257M96 in a 50pF load configuration?

The CD74HC257M96 achieves a typical propagation delay of 30ns at VCC = 4.5V and CL = 50pF, supporting reliable operation up to approximately 15–20MHz in worst-case timing paths. This assumes clean input edges (tr/tf ≤500ns at 4.5V) and proper PCB layout with local decoupling. The device does not specify a hard maximum clock frequency, as it is combinational logic - actual throughput depends on system-level setup/hold and routing delays. For CD74HC257M96-based designs targeting >10MHz, verify timing margins using TI's published tPLH/tPHL values across voltage and temperature corners.

Can CD74HC257M96 interface directly with 3.3V microcontrollers without level shifting?

Yes, CD74HC257M96 supports 2V–6V operation and has CMOS-compatible input thresholds: at VCC = 3.3V, VIH ≥2.1V (63% of VCC) and VIL ≤1.1V (33% of VCC), which align with standard 3.3V logic levels (VOH ≥2.4V, VOL ≤0.4V). Its inputs draw <1µA, eliminating loading concerns. Outputs swing rail-to-rail, so CD74HC257M96 can drive 3.3V inputs directly. However, if driving older 5V TTL loads, confirm VOH/VOL meet 2.0V/0.8V thresholds - at 3.3V VCC, CD74HC257M96 VOH ≈3.2V, satisfying TTL VIH minimum.

What is the purpose of the '96' suffix in CD74HC257M96, and how does it affect PCB assembly?

The '96' suffix in CD74HC257M96 indicates tape-and-reel packaging: 2500 units per large reel (330mm diameter, 16.4mm width), with pin 1 oriented in quadrant Q1 per EIA-481 standard. This format is optimized for automated SMT placement. The SOIC-16 footprint remains identical to tube-packaged variants (e.g., CD74HC257E), so no PCB redesign is needed. Reel packaging requires compatible feeder setup and confirms moisture sensitivity level (MSL) 1 - unlimited floor life at ≤30°C/60% RH, eliminating bake requirements prior to reflow.

How does the Output Enable (OE) pin behave during power-up, and what precautions prevent bus contention?

The OE pin on CD74HC257M96 is active LOW and has no internal pull-up; during power-up, its state is undefined until externally controlled. To prevent bus contention, tie OE to VCC through a 10kΩ resistor (ensuring HIGH/default high-Z state) or synchronize it with reset logic that asserts OE HIGH until system initialization completes. TI recommends adding a 100nF ceramic capacitor from OE to GND if routed near noisy signals. Since CD74HC257M96 outputs enter high-Z only when OE is HIGH, improper OE handling may cause unintended driving of shared buses - always validate OE sequencing in power-on-reset firmware.

Is CD74HC257M96 suitable for use in safety-critical automotive applications per ISO 26262?

CD74HC257M96 is not AEC-Q100 qualified and lacks ASIL-specific failure mode documentation, FIT rate reporting, or safety manual - therefore it is not recommended for ASIL-B or higher automotive safety goals. While its -55°C to +125°C rating meets temperature requirements for under-hood use, TI positions the CD74HC257M96 as a catalog-grade industrial logic device, not an automotive-qualified component. For ISO 26262-compliant designs, consider TI's automotive-grade alternatives like SN74HCS157QPWRQ1 (AEC-Q100 Grade 1, with safety documentation) - CD74HC257M96 may be used only in non-safety-related infotainment or body-control subsystems, subject to full FMEDA validation by the integrator.