Texas Instruments SN74AHC158NSR

Overview

SN74AHC158NSR from Texas Instruments is a quadruple 2-line to 1-line data selector/multiplexer IC operating from 2 V to 5.5 V, featuring an active-low common strobe (G) input, inverted output logic, and 16-pin SOP-NS package. It routes one of two 4-bit input sources to four outputs based on select control (A/B), with propagation delays as low as 4.1 ns at 5 V and ±8 mA output drive capability. It is used in digital logic routing, address/data bus selection, and signal path arbitration in industrial control and embedded systems.

For engineers reviewing the SN74AHC158NSR datasheet, SN74AHC158NSR pinout, SN74AHC158NSR application, or SN74AHC158NSR equivalent, key selection considerations include its 2–5.5 V supply range, guaranteed 16 ns max propagation delay at 3.3 V/50 pF, latch-up immunity >250 mA per JESD 17, and ESD robustness per JESD 22 (2000-V HBM).

Technical Context

The SN74AHC158NSR implements four independent 2:1 multiplexers sharing a single active-low strobe (G) and a common select line (A/B). When G is high, all Y outputs are forced high regardless of A/B or data inputs; when G is low, each Yn selects between An and Bn based on A/B state and inverts the chosen input. The device uses advanced CMOS (AHC) technology for high noise immunity and rail-to-rail output swing.

All inputs accept 0–VCC logic levels, outputs drive ±8 mA at 5 V, and the design supports mixed-voltage interfacing within its 2–5.5 V VCC range. Unused inputs must be tied to VCC or GND per TI SCBA004 guidance to prevent floating-node-induced current leakage or oscillation.

Key Specifications

Pinout & Package

SN74AHC158NSR is housed in a 16-pin SOP (Small Outline Package) with NS suffix, measuring 6.2 mm × 5.3 mm × 1.95 mm (max height), gull-wing leads, and JEDEC MO-150-compliant footprint. Pin 1 is marked by a notch or dot in the top-left corner of the package body.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LV158APWR and 74HC158PW, SN74AHC158NSR provides the optimal balance of speed (4.1 ns min), supply flexibility (2–5.5 V), and ruggedness (250 mA latch-up, 2000-V HBM), making it the preferred choice for real-time industrial and embedded multiplexing where timing predictability and environmental resilience are critical.

Availability

SN74AHC158NSR is available at Aetrix Electronics and suitable for industrial PLCs, embedded microcontroller bus arbitration, automated test equipment, and legacy interface adapters requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for SN74AHC158NSR 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 50 years of innovation in high-reliability logic families.

The SN74AHC158NSR belongs to the AHC (Advanced High-Speed CMOS) logic series, engineered for high-speed, low-power, and wide-supply digital interfacing in industrial, automotive, and communications infrastructure applications.

FAQ

What is the maximum clock frequency supported by SN74AHC158NSR?

The SN74AHC158NSR does not operate on a clock; it is a combinational logic device. Its usable toggle rate depends on propagation delay and load capacitance. With 15 pF load and 5 V supply, the maximum guaranteed toggle rate exceeds 100 MHz (based on 7.5 ns max tPLH/tPHL), though actual system-level performance depends on PCB layout and drive strength.

Does SN74AHC158NSR require external pull-up or pull-down resistors on unused inputs?

Yes. Per TI application report SCBA004, all unused inputs of SN74AHC158NSR - including A/B, G, and any unconnected data lines - must be tied to either VCC or GND. Floating CMOS inputs can cause increased ICC, logic instability, or localized heating due to shoot-through current in the input stage.

Can SN74AHC158NSR safely interface between 5 V and 3.3 V logic domains?

Yes. SN74AHC158NSR accepts input voltages up to 5.5 V (absolute max 7 V) while operating from a 3.3 V supply, and its outputs swing rail-to-rail. This allows direct connection of 5 V inputs to SN74AHC158NSR inputs and use of its 3.3 V outputs to drive 3.3 V logic, eliminating external level shifters in many cases.

What is the thermal resistance (θJA) of the SN74AHC158NSR in its NS package?

The SN74AHC158NSR in the SOP-NS package has a specified junction-to-ambient thermal resistance (θJA) of 64°C/W, measured per JESD 51-7 on a standard 4-layer JEDEC test board. This value assumes proper PCB copper pour and thermal vias under the exposed pad (if present) - though the NS package has no exposed thermal pad.

Is SN74AHC158NSR pin-compatible with older 74LS158 or 74HC158 devices?

SN74AHC158NSR shares identical pinout and function with 74HC158 and 74LS158 in the 16-pin DIP/SO/SSOP packages, including NS. However, electrical behavior differs: AHC offers higher speed, lower power, and wider VCC range than LS or HC. No PCB changes are needed for drop-in replacement, but verify timing margins and drive strength in the target system.