Texas Instruments SN74S151N

Overview

SN74S151N from Texas Instruments is a high-speed 8-line to 1-line data selector/multiplexer in a 16-pin PDIP package, featuring TTL-compatible inputs and outputs, propagation delay of 9 ns (max) at V_CC = 5 V, supply current of 34 mA (max), and operating temperature range of 0°C to 70°C. It performs digital signal routing in combinational logic systems, commonly used in address decoding, data path control, and ALU operand selection.

For engineers reviewing the SN74S151N datasheet, SN74S151N pinout, SN74S151N application, or SN74S151N equivalent, this page delivers verified functional identity, confirmed timing parameters, validated pin assignments, authentic package dimensions, and technically documented alternative options for industrial control, test equipment, and legacy TTL system design.

Technical Context

The SN74S151N implements a fully decoded 3-bit select input architecture (A, B, C) enabling one-of-eight data line selection (I₀–I₇) with complementary active-low enable (E̅) and dual complementary outputs (Y and Y̅). Its Schottky-clamped TTL circuitry ensures consistent noise immunity and predictable switching thresholds across the full commercial temperature range.

It operates exclusively from a single 5-V supply, requires no external biasing, and maintains output drive capability of –0.4 mA (high) and 8 mA (low) into standard TTL loads. The device supports wired-OR expansion via its Y̅ output and enables cascading through E̅ input chaining without additional logic gates.

Key Specifications

Pinout & Package

SN74S151N is housed in a 16-pin plastic dual in-line package (PDIP-N) with 0.3-inch body width, 0.1-inch lead pitch, and JEDEC MS-001AC outline. Pin 1 is located at the left end of the top row, identified by a notch or dot marking.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8:1 multiplexer applications.

Compared with SN74S151N, SN74LS151N trades speed for lower power and thermal load, while SN74F151N extends speed margin at higher supply current - both retain full pin and functional compatibility for drop-in replacement in existing PDIP-16 layouts.

Availability

SN74S151N is available at Aetrix Electronics and suitable for industrial control panels, legacy test instrumentation, and military-grade repair programs requiring stable component supply and long-term obsolescence management.

Supply support for SN74S151N 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 U.S.-based semiconductor company founded in 1930, specializing in analog, embedded processing, and logic solutions with broad industrial, automotive, and aerospace qualification.

The SN74S151N belongs to TI's 74S logic family, engineered for high-speed digital control in systems where TTL compatibility and nanosecond-level timing predictability are essential.

FAQ

What is the maximum operating frequency supported by SN74S151N?

The SN74S151N does not specify a maximum clock frequency in its datasheet because it is a combinational logic device without internal clocking. Its usable data rate depends on propagation delay (9 ns max) and system setup/hold timing. In practice, SN74S151N reliably supports data selection cycles up to approximately 30 MHz when interfaced with compatible TTL sources and loads. Always verify timing margins using worst-case t_pd, t_su, and t_h values from the official SN74S151N datasheet.

Is SN74S151N pin-compatible with SN74LS151N?

Yes, SN74S151N is fully pin-compatible with SN74LS151N - both share identical PDIP-16 packaging, pin numbering, terminal functions, and truth table behavior. The only differences are electrical: SN74S151N offers faster propagation delay (9 ns vs. 22 ns) and higher supply current (34 mA vs. 22 mA). This makes SN74S151N a direct performance upgrade in existing SN74LS151N layouts without PCB changes.

Does SN74S151N support mixed-voltage operation (e.g., 3.3 V inputs)?

No, SN74S151N is a strict 5-V TTL device and does not support 3.3 V logic inputs. Its input thresholds (V_IL = 0.8 V max, V_IH = 2.0 V min) require minimum 2.0 V for HIGH recognition, but 3.3 V CMOS outputs may exceed its absolute maximum input voltage rating (V_I = 5.5 V) under transient conditions. For 3.3 V system integration, use a level translator or select a 74LVC-series multiplexer instead of SN74S151N.

Can SN74S151N outputs drive LEDs directly?

Yes, SN74S151N can drive standard 5-mm LEDs directly when configured in active-low mode using the Y̅ output. With I_OL = 8 mA and V_OL ≤ 0.5 V, it supports typical red/green LEDs (2.0 V forward voltage) with a 330 Ω series resistor at 5 V supply. Avoid using the Y output for LED drive unless buffered, as its I_OH = –0.4 mA limits sourcing capability. Always confirm LED current and thermal dissipation against SN74S151N's total power rating.

Where is the official SN74S151N datasheet published?

The official SN74S151N datasheet is published by Texas Instruments and available for download at ti.com under part number SN74S151. It includes complete AC/DC specifications, recommended operating conditions, truth tables, timing diagrams, and application examples. Aetrix Electronics recommends consulting the latest revision (SLRS017 or newer) for accurate thermal derating curves, MSL handling guidance, and updated reliability data before final design sign-off.