Texas Instruments CD40257BM96G4

Overview

CD40257BM96G4 from Texas Instruments is a CMOS quad 2-line-to-1-line data selector/multiplexer with common strobe control, operating across –55°C to +125°C, featuring 100% tested DC parameters, TTL-compatible inputs, and 16-pin SOIC (D) package. It enables bidirectional data routing in digital logic systems such as address/data bus switching and serial-to-parallel conversion.

For engineers reviewing the CD40257BM96G4 datasheet, CD40257BM96G4 pinout, CD40257BM96G4 application, or CD40257BM96G4 equivalent, key selection considerations include its dual-supply voltage range (3V–18V), propagation delay of 80 ns at 5V, high noise immunity (≥45% V_DD), and compatibility with legacy CD4000B-series logic families.

Technical Context

The CD40257BM96G4 implements four independent 2:1 multiplexers sharing a single active-low strobe (STB) input that disables all outputs when high. Each channel selects between two data inputs (A_n, B_n) based on a common select line (S), with output polarity matching input logic level.

It uses standard CMOS silicon-gate technology, ensuring low static current (≤1 µA at 18 V), symmetrical output drive capability (±4.2 mA at 15 V), and full buffered inputs/outputs for fan-out ≥10 to CD4000B loads. No internal latching or clocking is present-operation is purely combinational.

Key Specifications

Pinout & Package

CD40257BM96G4 is housed in a 16-pin Small Outline Integrated Circuit (SOIC) package (Package Code D), 7.5 mm wide, with 1.27 mm pitch, RoHS-compliant NiPdAu lead finish, and Moisture Sensitivity Level 1 (unlimited floor life at <30°C/60% RH).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar data selector/multiplexer applications.

Compared with CD4053BE and SN74LV4052APWR, the CD40257BM96G4 uniquely combines quad 2:1 digital multiplexing, 3–18 V operation, and military-grade temperature range in a single SOIC package-making it irreplaceable in mixed-voltage, high-reliability embedded systems requiring deterministic logic behavior.

Availability

CD40257BM96G4 is available at Aetrix Electronics and suitable for industrial control panels, avionics display interfaces, automotive body controllers, and automated test equipment requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for CD40257BM96G4 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 headquartered in Dallas, Texas, delivering analog, embedded processing, and logic products for industrial, automotive, and communications markets since 1930.

The CD40257B series belongs to TI's legacy CMOS logic portfolio, designed specifically for high-reliability, wide-temperature, and mixed-voltage digital control applications where compatibility with older 4000-series systems remains critical.

FAQ

What is the function of the STB pin on the CD40257BM96G4?

The STB (strobe) pin on the CD40257BM96G4 is an active-low enable input that globally disables all four multiplexer outputs when high. When STB is low, outputs Y₀–Y₃ reflect the selected inputs (A_n or B_n) based on the S input state. This allows synchronous gating of data paths in time-critical control sequences without affecting individual channel select logic. The CD40257BM96G4 datasheet specifies STB threshold compatibility with TTL and CMOS logic families across its full 3–18 V supply range.

Does the CD40257BM96G4 support bidirectional signal flow?

No, the CD40257BM96G4 is a unidirectional digital multiplexer: signals flow only from inputs A₀–A₃/B₀–B₃ to outputs Y₀–Y₃. It does not support reverse signal propagation or analog pass-through. Its CMOS output structure is designed for sourcing/sinking digital logic levels-not for analog switching. For bidirectional or analog applications, TI recommends alternatives like CD4053BE. The CD40257BM96G4 specification sheet explicitly defines it as a "quad 2-line-to-1-line data selector," confirming its dedicated forward-path logic role.

What is the maximum clock frequency supported by the CD40257BM96G4?

The CD40257BM96G4 has no internal clock; it is a purely combinational logic device. Its usable data rate depends on propagation delay: 80 ns maximum at V_DD = 5 V implies a theoretical upper toggle limit of ~6 MHz for repetitive selection patterns. At V_DD = 15 V, t_PD improves to 30 ns (~12 MHz). System-level timing must account for setup/hold times of upstream drivers and downstream loads. The CD40257BM96G4 datasheet provides detailed AC timing diagrams for worst-case edge-to-edge delays under defined load conditions.

Is the CD40257BM96G4 pin-compatible with the CD40257BE PDIP version?

Yes, the CD40257BM96G4 (SOIC-16) and CD40257BE (PDIP-16) share identical pin numbering, signal assignment, and electrical functionality. Both follow JEDEC MS-012 for SOIC and MS-001 for PDIP footprints, with matching pin 1 location (notch/dot), V_DD (pin 16), V_SS (pin 7), and I/O ordering. Mechanical dimensions differ, but PCB layout adaptation requires only footprint change-not netlist or schematic revision. The CD40257BM96G4 datasheet confirms functional and pinout equivalence across all CD40257B suffixes including E, M, and F3A packages.

Can the CD40257BM96G4 operate at 2.5 V supply voltage?

No, the CD40257BM96G4 is not characterized or guaranteed for operation below 3 V. Its absolute minimum supply voltage is 3 V per the official Texas Instruments datasheet (SCHS108C), with DC parameters (e.g., V_OH, V_OL, noise margin) specified only from 3 V to 18 V. At 2.5 V, output drive strength degrades significantly, propagation delay increases unpredictably, and input thresholds become undefined. For 2.5 V systems, TI recommends the SN74LVC157A or similar LVCMOS logic. The CD40257BM96G4 design assumes minimum 3 V for reliable CMOS threshold behavior and rail-to-rail output swing.