Texas Instruments SN74HC158ANSR

Overview

SN74HC158ANSR from Texas Instruments is a quad 2-input inverting multiplexer IC used for data routing and logic selection in digital systems. It features four independent 2:1 multiplexers with common select (S) and active-low enable (E), delivers inverted outputs, operates across 2.0–6.0 V supply, and supports −40 °C to +125 °C ambient temperature - commonly deployed in industrial control logic and address/data bus switching.

For engineers reviewing the SN74HC158ANSR datasheet, SN74HC158ANSR pinout, SN74HC158ANSR application, or SN74HC158ANSR equivalent, key selection considerations include its inverting output behavior versus non-inverting alternatives, propagation delay under load (12 ns typical at 5 V/15 pF), JEDEC 7A compliance, DIP-16 package footprint, and functional equivalence to SN74HC157 with polarity inversion.

Technical Context

The SN74HC158ANSR implements four independent 2:1 multiplexer channels sharing one select input (S) and one active-low enable (E). Each channel selects between two data inputs (nI0/nI1) and drives an inverted output (nY), with logic equation nY = E·(nI1·S + nI0·S̅).

It uses high-speed Si-gate CMOS technology, achieves pin compatibility with LSTTL, and meets JEDEC standard no. 7A. Its operation is fully defined across 2.0–6.0 V supply and −40 °C to +125 °C, with static input leakage ≤±1.0 µA and dynamic power dissipation modeled via CPD = 40 pF.

Key Specifications

Pinout & Package

SN74HC158ANSR is supplied in a plastic dual in-line package (DIP-16) with 300-mil body width and through-hole mounting. Pin 1 is index-marked; pin 8 is GND and pin 16 is VCC.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad 2-input multiplexer applications.

Compared with SN74HC158ANSR, SN74HC157N removes inversion - simplifying interface where complemented outputs are unnecessary - while MC74HC158N offers second-source assurance without functional or layout impact.

Availability

SN74HC158ANSR is available at Aetrix Electronics and suitable for industrial control systems, legacy equipment refurbishment, and educational electronics kits requiring stable component supply and long-term obsolescence management.

Supply support for SN74HC158ANSR 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 specializing in analog and embedded processing technologies, with leadership in logic, power management, and signal chain solutions.

The SN74HC158ANSR belongs to TI's 74HC high-speed CMOS logic family, designed for pin-compatible upgrades of legacy TTL systems while delivering lower power consumption and wider voltage operation.

FAQ

What is the maximum clock frequency supported by SN74HC158ANSR?

The SN74HC158ANSR does not operate on a clock signal - it is a combinational logic device with propagation delay as the key timing parameter. At VCC = 5 V and CL = 15 pF, tPHL/tPLH is 12 ns typical, supporting data switching up to approximately 40 MHz in worst-case cascaded paths. System-level maximum toggle rate depends on fanout, trace length, and load capacitance - not an internal clock.

Does SN74HC158ANSR support 3.3 V operation?

Yes, SN74HC158ANSR supports 3.3 V operation within its specified supply range of 2.0 V to 6.0 V. At VCC = 3.3 V, VIH is guaranteed ≥2.31 V and VIL ≤1.09 V per datasheet Table 7, providing >30% noise margin. Output drive remains functional at ±4 mA, making it interoperable with 3.3 V CMOS and mixed-voltage systems.

How does the enable input (E) affect output states in SN74HC158ANSR?

When E is HIGH, all four outputs (1Y–4Y) are forced HIGH regardless of S or input states - this is a hard-wired override, not high-impedance. Only when E is LOW does the multiplexer respond to S and data inputs. This behavior differs from tri-state devices; SN74HC158ANSR has no high-impedance mode - outputs are always driven.

Can SN74HC158ANSR replace SN74LS158 in existing designs?

SN74HC158ANSR is pin-compatible with SN74LS158 and meets JEDEC 7A, but requires verification of VCC (LS uses 5 V only; HC supports 2–6 V) and fanout (HC drives lighter loads than LS). Input thresholds differ: LS VIH ≈ 2.0 V, HC VIH ≈ 3.15 V at 4.5 V. Direct replacement is feasible in 5 V systems with adequate noise margin, but not guaranteed in marginal or high-noise environments.

What is the power dissipation of SN74HC158ANSR at 5 V and 1 MHz toggle rate?

Using PD = CPD × VCC² × fi × N, with CPD = 40 pF, VCC = 5 V, fi = 1 MHz, and N = 4 switching inputs: PD ≈ 40 × 25 × 1 × 4 = 4000 µW = 4 mW. This excludes dynamic load contribution (∑CL×VCC²×fo). Total dissipation remains well below the DIP-16 package limit of 750 mW, confirming suitability for continuous operation in thermally constrained layouts.