Texas Instruments SN74LVC257APWT

Overview

SN74LVC257APWT from Texas Instruments is a quadruple 2-line to 1-line data selector/multiplexer with 3-state outputs, designed for 1.65V–3.6V V_CC operation. It supports mixed-voltage interfacing (inputs tolerate up to 5.5V), delivers ≤4.6ns propagation delay at 3.3V, and enables bus-organized signal routing in compact TSSOP-16 packaging - used in I/O expansion and level translation within telecom infrastructure and server backplanes.

For engineers reviewing the SN74LVC257APWT datasheet, SN74LVC257APWT pinout, SN74LVC257APWT application, or SN74LVC257APWT equivalent, key selection criteria include its 3-state output control, voltage-tolerant inputs, sub-5ns timing performance, thermal resistance (R_θJA = 141.8°C/W), and compatibility with 1.65V–3.6V logic domains in space-constrained industrial and networking designs.

Technical Context

The SN74LVC257APWT implements four independent 2:1 multiplexers sharing a common active-low output-enable (OE) input and a single select line (A/B) that determines whether each Y output passes A or B input. Its CMOS design ensures balanced drive strength and rail-to-rail output swing across the full 1.65V–3.6V supply range.

All inputs are overvoltage tolerant to 5.5V regardless of V_CC, enabling seamless interfacing between 3.3V systems and legacy 5V peripherals. The 3-state outputs isolate the bus when OE is high, preventing contention during power-up/down sequences - critical for hot-swap-capable backplane architectures.

Key Specifications

Pinout & Package

Packaged in a 16-pin Thin Shrink Small Outline Package (TSSOP-PW), SN74LVC257APWT measures 5.00mm × 6.4mm with 0.65mm lead pitch and exposed pad not present. The package supports automated assembly and offers moderate thermal performance for board-level integration.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC157APWR and 74LVC257PW,118, the SN74LVC257APWT provides identical functionality with optimized small-reel packaging for prototyping and low-volume production, while maintaining best-in-class 4.6ns propagation delay and TI's full industrial qualification.

Availability

SN74LVC257APWT is available at Aetrix Electronics and suitable for cable modem termination systems, network switches, and motor driver control requiring stable component supply, consistent parametric performance, and long-term industrial lifecycle support.

Supply support for SN74LVC257APWT 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 connectivity technologies, with decades of experience in high-reliability logic and interface solutions.

The SN74LVC257APWT belongs to TI's LVC logic family, engineered for low-voltage, high-speed, mixed-signal interfacing in industrial, telecom, and computing applications where voltage translation and bus isolation are critical.

FAQ

What is the maximum input voltage tolerance for SN74LVC257APWT?

The SN74LVC257APWT supports input voltages up to 5.5V regardless of V_CC level - a key feature enabling direct interfacing with 5V logic sources while operating from 1.65V–3.6V supplies. This eliminates external level-shifting circuitry in mixed-voltage systems and is confirmed in Section 5.3 of the official TI datasheet SCAS294Q.

Does SN74LVC257APWT require external pull-up resistors on the OE pin?

Yes - to ensure high-impedance outputs during power-up and power-down, OE must be tied to V_CC through an external pull-up resistor. The minimum value depends on the driving source's current-sinking capability, as stated in Section 7.3 of the SN74LVC257APWT datasheet. Failure to do so risks bus contention or undefined output states.

What is the thermal resistance (R_θJA) of SN74LVC257APWT in its TSSOP package?

The SN74LVC257APWT in the PW (TSSOP-16) package has a junction-to-ambient thermal resistance of 141.8°C/W, as specified in Section 5.4 of the TI datasheet. This value assumes standard JEDEC 2-layer board conditions and informs PCB layout decisions such as copper area and airflow requirements for thermal management.

Can SN74LVC257APWT operate reliably at 1.65V supply voltage?

Yes - SN74LVC257APWT is fully specified down to 1.65V V_CC, with guaranteed timing (t_pd ≤13.5ns), drive strength (I_OL/I_OH ≥4mA), and logic thresholds across the full –40°C to +85°C temperature range. This makes it suitable for ultra-low-power battery-operated and energy-efficient industrial systems.

How many independent multiplexer channels does SN74LVC257APWT provide?

The SN74LVC257APWT integrates four independent 2-line to 1-line multiplexers, each with dedicated A/B inputs and Y output. All four share a common A/B select line and active-low OE control, allowing synchronized channel selection and simultaneous 3-state output control - ideal for parallel data path management in bus architectures.