Texas Instruments SN74LVC257ADBR

Overview

SN74LVC257ADBR 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 features overvoltage-tolerant inputs for use in bus-organized systems such as I/O expanders and network switches.

For engineers reviewing the SN74LVC257ADBR datasheet, SN74LVC257ADBR pinout, SN74LVC257ADBR application, or SN74LVC257ADBR equivalent, key selection criteria include its 16-pin SSOP package, 3-state output enable control, 5.5V-tolerant inputs, and guaranteed t_pd performance across 1.65V–3.6V supply range.

Technical Context

The SN74LVC257ADBR implements four independent 2:1 multiplexers sharing a common active-low output-enable (OE) input and a single select line (A/B). Each channel routes either input A or B to its corresponding Y output based on the logic level of A/B, while OE controls high-impedance state across all four outputs simultaneously.

Its CMOS design enables bidirectional voltage translation: inputs accept 0–5.5V regardless of V_CC, allowing seamless interface between 3.3V logic and legacy 5V peripherals without external level shifters. The device operates reliably from –40°C to +85°C and meets JESD 17 latch-up (>250mA) and JESD 22 ESD standards (2000V HBM, 200V MM).

Key Specifications

Pinout & Package

SN74LVC257ADBR uses a 16-pin SSOP (DB) package measuring 6.20 mm × 7.8 mm (body size: 6.20 mm × 5.30 mm), optimized for space-constrained industrial PCBs with standard surface-mount assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC157ADBR and 74LVCH16257MTDX, SN74LVC257ADBR uniquely balances 4-channel density, 5.5V input tolerance, and SSOP footprint-making it ideal for industrial I/O expansion where voltage domain bridging and board area are both critical constraints.

Availability

SN74LVC257ADBR is available at Aetrix Electronics and suitable for industrial PLCs, telecom infrastructure, and test equipment requiring stable component supply, long-term manufacturability, and consistent parametric performance across production batches.

Supply support for SN74LVC257ADBR 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 and embedded processing technologies, with decades of experience delivering high-reliability logic, interface, and power management solutions.

The SN74LVC257A product line targets voltage-flexible digital signal routing in industrial, communications, and instrumentation systems-designed specifically to simplify mixed-voltage board design while maintaining speed, noise immunity, and thermal robustness.

FAQ

What is the maximum input voltage rating for SN74LVC257ADBR?

The SN74LVC257ADBR accepts input voltages up to 5.5V regardless of V_CC level, as confirmed in Section 5.1 Absolute Maximum Ratings and Section 5.3 Recommended Operating Conditions of the TI datasheet. This overvoltage tolerance allows direct interfacing with 5V logic families while operating from a 1.65V–3.6V supply, making SN74LVC257ADBR suitable for mixed-voltage system integration without external level-shifting components.

Does SN74LVC257ADBR support true bidirectional level translation?

No, SN74LVC257ADBR does not perform bidirectional level translation. It is a unidirectional multiplexer: inputs tolerate up to 5.5V, but outputs swing only between GND and V_CC (1.65V–3.6V). Therefore, SN74LVC257ADBR translates 5V inputs down to 3.3V/2.5V logic levels, but cannot translate low-voltage signals up to 5V. For bidirectional translation, a dedicated level shifter such as TXS0108E is required alongside SN74LVC257ADBR.

What is the recommended bypass capacitor for SN74LVC257ADBR?

Texas Instruments recommends a 0.1µF ceramic bypass capacitor placed as close as possible to the V_CC pin of SN74LVC257ADBR, per Section 3 Power Supply Recommendations in the datasheet. This capacitor stabilizes the supply against transient current demands during output switching and minimizes ground bounce (VOLP < 0.8V typical at 3.3V). For boards with multiple SN74LVC257ADBR units or high-speed adjacent logic, paralleling a 0.01µF capacitor may further suppress high-frequency noise.

How does the OE pin function on SN74LVC257ADBR?

The OE (output enable) pin on SN74LVC257ADBR is an active-low control that places all four Y outputs (1Y–4Y) into high-impedance state when driven high. When OE is low, the outputs reflect the selected inputs (A or B) based on the A/B select line. This synchronous 3-state control enables SN74LVC257ADBR to share data buses safely-preventing contention when multiple devices drive the same lines. TI recommends pulling OE up to V_CC via a resistor during power-up to ensure defined initial state.

Is SN74LVC257ADBR pin-compatible with other members of the LVC257A family?

Yes, SN74LVC257ADBR is pin-compatible with all other package variants of the SN74LVC257A family-including SOIC (D), TSSOP (PW), VQFN (RGY), and WQFN (BQB)-as confirmed by identical pin numbering and function definitions in Figures 4-1 and 4-2 of the TI datasheet. All variants share the same 16-pin layout, signal assignments (e.g., Pin 1 = 1A, Pin 15 = OE), and electrical behavior, enabling drop-in replacement across packages based on thermal, density, or assembly requirements without PCB redesign.