Texas Instruments CD40257BM

Overview

CD40257BM from Texas Instruments is a CMOS 4-bit dual 1-of-4 data selector/multiplexer with common strobe control, operating across -55°C to +125°C, featuring 16-pin SOIC (D) package, 3V–18V supply range, and TTL-compatible inputs. It enables bidirectional data routing in digital logic systems such as address decoding and bus management.

For engineers reviewing the CD40257BM datasheet, CD40257BM pinout, CD40257BM application, or CD40257BM equivalent, key selection considerations include its dual 4:1 multiplexing capability, wide V_DD tolerance, low quiescent current, and compatibility with legacy 4000B-series logic families in industrial and aerospace control systems.

Technical Context

The CD40257BM implements two independent 4-input multiplexers sharing a common strobe (G) and two select lines (S0, S1), each selecting one of four data inputs (I0–I3) per channel to drive corresponding outputs (Y0, Y1). All inputs are buffered and fully static.

It uses standard CMOS silicon-gate technology with symmetrical output drive, rail-to-rail voltage swing, and guaranteed noise margins over full temperature and supply ranges. Input thresholds are referenced to V_DD/2, enabling robust interfacing with both CMOS and TTL logic sources.

Key Specifications

Pinout & Package

CD40257BM is housed in a 16-pin SOIC (D) package, 7.5 mm wide, with 1.27 mm pitch, RoHS-compliant NiPdAu lead finish, and MSL Level-1 rating for unlimited reflow exposure.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 4-bit dual multiplexer applications.

Compared with CD4052BE and 74HC153, the CD40257BM uniquely combines dual digital multiplexing with common strobe control, -55°C to +125°C operation, and 3V–18V flexibility-making it irreplaceable in ruggedized, mixed-supply, or long-lifecycle embedded control designs.

Availability

CD40257BM is available at Aetrix Electronics and suitable for industrial automation, aerospace subsystems, and automotive body electronics requiring stable component supply across extended temperature and long product lifecycles.

Supply support for CD40257BM 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 CMOS logic families.

The CD40257BM belongs to TI's 4000B-series logic portfolio, designed specifically for robust, wide-supply, extended-temperature digital control in mission-critical and legacy-compatible systems.

FAQ

What is the function of the strobe pin (Pin 7) on the CD40257BM?

The strobe pin (G, Pin 7) is an active-low enable that simultaneously controls both multiplexer outputs. When high, Y0 and Y1 are forced low regardless of select or input states; when low, outputs reflect the selected inputs. This allows synchronized gating of dual data paths in the CD40257BM, critical for time-aligned sampling or fault-isolation schemes.

Does the CD40257BM support operation at 3.3V logic levels?

Yes, the CD40257BM operates reliably down to 3V V_DD, making it compatible with 3.3V systems. Its TTL-compatible inputs recognize 2.0V as a valid logic high at 3.3V supply, and output swing reaches >3.0V under typical loads - enabling direct interfacing with 3.3V microcontrollers without level shifters in the CD40257BM application.

Is the CD40257BM pin-compatible with other 16-pin 4000B-series devices?

No - the CD40257BM has a unique pinout optimized for dual 4:1 multiplexing, including dedicated I/O groups and a shared strobe. It is not pin-compatible with CD4051, CD4052, or CD4067. Always verify against the official CD40257BM pin diagram before PCB layout or replacement.

What is the maximum clock/data switching frequency supported by the CD40257BM?

The CD40257BM is a static CMOS device with no internal clock; its usable data rate depends on propagation delay and system setup/hold timing. At 10V supply, t_PD ≤ 60 ns supports reliable operation up to ~5 MHz toggle rates in well-terminated, low-capacitance layouts - confirmed by timing analysis in the CD40257BM datasheet.

Can the CD40257BM be used in place of the CD4052 for digital signal selection?

Only if the application requires dual independent 4:1 selection with common strobe control and wide supply range. The CD4052 is a single differential analog switch lacking TTL-compatible inputs, strobe, and guaranteed digital noise margins. For pure digital routing, the CD40257BM provides superior noise immunity, defined logic thresholds, and deterministic behavior - unlike the CD4052 which is optimized for analog signals.