Texas Instruments SN74LVC257D

Overview

SN74LVC257D from Texas Instruments is a quadruple 2-line to 1-line data selector/multiplexer with 3-state outputs, designed for 1.65-V to 3.6-V V_CC operation. It routes four independent 2-input data pairs to four outputs under select control (A/B), enables bus isolation via active-low output-enable (OE), and supports mixed-voltage interfacing with 5.5-V-tolerant inputs.

For engineers reviewing the SN74LVC257D datasheet, SN74LVC257D pinout, SN74LVC257D application, or SN74LVC257D equivalent, key selection criteria include its 3.6-V max supply, ±24-mA drive strength at 3.0-V V_CC, 4.6-ns typical propagation delay, 3-state bus-hold capability, and D-package thermal impedance of 113°C/W.

Technical Context

This device implements four independent 2:1 multiplexers in a single IC, each selecting between two input signals (A or B) based on a shared A/B select line. All outputs are controlled collectively by OE, entering high-impedance state when OE = HIGH.

Its EPIC™ submicron CMOS process ensures latch-up immunity (>250 mA per JESD 17), ESD robustness (>2000 V HBM), and ground-bounce/undershoot suppression (VOLP < 0.8 V, VOHV > 2 V at 3.3 V). Inputs tolerate up to 5.5 V regardless of V_CC, enabling level translation in mixed 3.3-V/5-V systems.

Key Specifications

Pinout & Package

SN74LVC257D uses a 16-pin plastic small-outline (SOIC) package (D package), 7.5 mm × 10.3 mm body, 1.75 mm height, 1.27 mm pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVCH257A and 74LVC157D, the SN74LVC257D provides the most direct implementation of quad synchronized 2:1 selection with minimal board area (D package), lowest propagation skew, and proven industrial temperature reliability - making it ideal for space-constrained, timing-critical bus multiplexing.

Availability

SN74LVC257D is available at Aetrix Electronics and suitable for industrial automation, embedded test instrumentation, and automotive body electronics requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for SN74LVC257D 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 90 years of innovation in industrial, automotive, and communications markets.

The SN74LVC257D belongs to TI's LVC logic family, engineered for low-voltage, high-speed, mixed-signal interface applications where signal integrity, power efficiency, and interoperability across voltage domains are essential.

FAQ

What is the maximum supply voltage rating for SN74LVC257D?

The absolute maximum supply voltage for SN74LVC257D is 6.5 V, but recommended operation is strictly limited to 1.65 V to 3.6 V. Operating above 3.6 V risks violating functional specifications and may cause premature wear or latch-up. The SN74LVC257D is not rated for continuous 5-V V_CC operation - use only within its specified 1.65–3.6-V window for guaranteed performance and reliability.

Does SN74LVC257D support 5-V input signals while powered from 3.3 V?

Yes, SN74LVC257D accepts input voltages up to 5.5 V regardless of V_CC, enabling seamless interfacing with 5-V logic devices while operating from a 3.3-V supply. This feature is explicitly confirmed in the datasheet's "Inputs Accept Voltages to 5.5 V" statement and electrical characteristics table. The SN74LVC257D leverages this capability to serve as a level translator in mixed-voltage systems without external components.

What is the purpose of the A/B pin on SN74LVC257D?

The A/B pin is a shared select line that determines, for all four multiplexer channels simultaneously, whether input A or input B is routed to the corresponding output (1Y–4Y). When A/B = LOW, all outputs reflect their respective A inputs (1A→1Y, etc.); when A/B = HIGH, they reflect B inputs. This synchronous selection simplifies control logic and ensures phase-aligned switching across all channels in the SN74LVC257D.

How does SN74LVC257D ensure safe operation during power-up?

To guarantee high-impedance outputs during power sequencing, the OE pin of SN74LVC257D must be tied to V_CC through an external pull-up resistor. This prevents bus contention before firmware initializes OE control. The minimum resistor value depends on the driver's sink capability, as specified in the datasheet. This design requirement is integral to the SN74LVC257D's safe integration into systems with asynchronous power rails.

Is SN74LVC257D pin-compatible with SN74LVC257A?

Yes, SN74LVC257D and SN74LVC257A share identical pinouts, electrical specifications, and functional behavior - the "D" suffix denotes the SOIC (D) package, while "A" indicates the device revision. Both are fully interchangeable in layout and firmware. The SN74LVC257D is the package-specific designation for the SN74LVC257A device in 16-pin SOIC form, with no functional or timing differences.