Texas Instruments SN74LVC257ADB

Overview

SN74LVC257ADB 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 OE, and supports mixed-voltage interfacing (inputs tolerate up to 5.5 V) in embedded digital systems.

For engineers reviewing the SN74LVC257ADB datasheet, SN74LVC257ADB pinout, SN74LVC257ADB application, or SN74LVC257ADB equivalent, key selection criteria include its 3.6-V max supply rating, 24-mA output drive at 3.0 V, –40°C to 85°C temperature range, 14-pin SSOP (DB) package, and translation capability between 3.3-V and 5-V logic domains.

Technical Context

The SN74LVC257ADB implements four independent 2:1 multiplexers sharing one common select line (A/B) and one global 3-state enable (OE). Each channel selects between two inputs (e.g., 1A/1B) and drives a dedicated output (1Y) with high-impedance state when OE = HIGH.

Its EPIC™ submicron CMOS process ensures low dynamic power, rail-to-rail input tolerance (0–5.5 V), and robust ESD protection (>2000 V HBM). The device meets JESD 17 latch-up immunity (>250 mA) and exhibits controlled ground bounce (<0.8 V) and undershoot (>2 V) at 3.3 V.

Key Specifications

Pinout & Package

SN74LVC257ADB is housed in a 14-pin Shrink Small-Outline Package (SSOP, DB), 5.3 mm × 6.2 mm body, 0.65 mm pitch, with exposed pad not present. Pin numbering follows standard DB top-view orientation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 2:1 multiplexer applications.

Compared with SN74LVCH257A and 74LVC157AD, the SN74LVC257ADB delivers optimized thermal resistance in SSOP packaging and eliminates bus-hold overhead where input biasing is already managed externally - making it ideal for high-density, cost-controlled industrial control modules.

Availability

SN74LVC257ADB is available at Aetrix Electronics and suitable for industrial control panels, embedded instrumentation, and programmable logic interface modules requiring stable component supply and long-term manufacturability.

Supply support for SN74LVC257ADB 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 decades of innovation in high-reliability logic families.

The SN74LVC257ADB belongs to TI's LVC (Low-Voltage CMOS) logic series, engineered for low-power, mixed-voltage interoperability in industrial, automotive, and communications infrastructure applications.

FAQ

What is the maximum input voltage the SN74LVC257ADB can tolerate?

The SN74LVC257ADB accepts input voltages from –0.5 V to 5.5 V, independent of V_CC. This allows direct connection to 5-V logic sources while operating from a 3.3-V or lower supply - a key feature enabling voltage translation without external components. The absolute maximum rating is strictly limited to 5.5 V to prevent damage.

Does the SN74LVC257ADB support hot insertion or live bus swapping?

The SN74LVC257ADB is not explicitly rated for hot insertion. Its inputs tolerate 5.5 V and outputs enter high-impedance when OE is HIGH, but the device lacks I_off protection or power-off isolation. For live-swap applications, external series resistors and careful sequencing of OE/V_CC are recommended - always verify behavior under actual system conditions before deployment.

How does the SN74LVC257ADB handle power-up sequencing?

To ensure outputs remain in high-impedance during power-up, OE must be held HIGH (e.g., pulled to V_CC via a resistor) until V_CC stabilizes. The SN74LVC257ADB does not have built-in power-on reset; improper OE biasing may cause transient bus contention. TI recommends a minimum 10-kΩ pull-up for typical driver sink capability.

Can the SN74LVC257ADB be used as a level shifter between 3.3-V and 5-V domains?

Yes - the SN74LVC257ADB functions as a unidirectional level shifter when used in pass-through mode: 5-V inputs are safely accepted, and outputs swing rail-to-rail between GND and the applied V_CC (e.g., 3.3 V). However, it does not translate in the reverse direction (3.3-V output to 5-V input) without additional buffering due to VOH limitations.

What is the thermal resistance (θ_JA) of the SN74LVC257ADB package?

The SN74LVC257ADB in the DB (SSOP) package has a specified junction-to-ambient thermal resistance (θ_JA) of 131°C/W under JEDEC-standard PCB conditions. This value assumes a two-layer board with 1-in² copper pour; actual thermal performance improves with enhanced layout practices such as internal ground/power planes and thermal vias.