Texas Instruments SN74HC158DR

Overview

SN74HC158DR from Texas Instruments is a high-speed CMOS 2-line-to-4-line data selector/multiplexer with active-low strobe and inverted outputs. It operates across 2 V to 6 V, delivers 11 ns typical propagation delay at 6 V, provides ±6-mA output drive at 5 V, and supports up to 15 LSTTL loads - used in digital logic routing, address decoding, and bus multiplexing in industrial control systems.

For engineers reviewing the SN74HC158DR datasheet, SN74HC158DR pinout, SN74HC158DR application, or SN74HC158DR equivalent, key selection criteria include its dual-input 4-channel inverted MUX architecture, SOIC-16 package compatibility, wide supply voltage range, low ICC (80 µA max), and guaranteed LSTTL drive capability without external buffers.

Technical Context

The SN74HC158DR implements four independent 2:1 multiplexers sharing a common active-low enable (G) and select (A/B) inputs. Each channel selects between two complementary data sources (A or B) and routes the chosen input - inverted - to its dedicated output (1Y–4Y).

Its logic diagram confirms full internal inversion: all outputs are active-low complements of selected inputs. The device uses standard HC-series CMOS circuitry with Schmitt-trigger input thresholds only on G and A/B pins per TI's functional description - no hysteresis on data inputs (1A–4B).

Key Specifications

Pinout & Package

SN74HC158DR is housed in a 16-pin SOIC (D) package measuring 10.4 mm × 7.4 mm × 2.0 mm max height, with 1.27 mm pitch, RoHS-compliant NiPdAu lead finish, and JEDEC-standard MSL Level-1 rating.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HC158DR, SN74HCT158DR offers tighter input threshold alignment with TTL logic but sacrifices 2 V operation; 74LCX158MTR enables faster 3.3 V operation but eliminates 5 V compatibility - making SN74HC158DR the optimal balance of voltage flexibility, drive strength, and industrial temperature support.

Availability

SN74HC158DR is available at Aetrix Electronics and suitable for industrial PLC I/O multiplexing, microcontroller address decoding, digital test equipment signal routing, and legacy bus interface logic requiring stable component supply across extended temperature ranges.

Supply support for SN74HC158DR 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 ICs, with over 90 years of innovation in industrial, automotive, and communications markets.

The SN74HC158DR belongs to TI's 74HC logic family - engineered for high noise immunity, low power, and broad voltage operation in industrial control, instrumentation, and digital system design.

FAQ

What is the logic polarity of SN74HC158DR outputs?

The SN74HC158DR outputs are inverted: each Y output (1Y–4Y) presents the logical complement of the selected input (A or B). When A/B = low and G = low, 1Y = NOT(1A); when A/B = high and G = low, 1Y = NOT(1B). This inversion is inherent to the device architecture and cannot be disabled.

Can SN74HC158DR operate reliably at 3.3 V supply?

Yes, SN74HC158DR is fully specified from 2 V to 6 V, including 3.3 V. At VCC = 3.3 V, it maintains VIH = 2.0 V min, VIL = 1.0 V max, tpd ≈ 15 ns (CL = 50 pF), and IO = ±4 mA - meeting requirements for mixed-voltage 3.3 V/5 V system interconnects without level translation.

Is SN74HC158DR pin-compatible with older 74LS158 devices?

Yes, SN74HC158DR shares identical pinout, function table, and logic behavior with 74LS158 and 74ALS158, including active-low strobe (G), common select (A/B), and inverted outputs. However, it draws significantly less current and operates across wider voltage and temperature ranges.

What is the maximum capacitive load SN74HC158DR can drive?

SN74HC158DR is characterized up to CL = 150 pF in the datasheet. At VCC = 6 V, tpd increases to 49 ns (max) and tt to 53 ns (max) under 150 pF loading. For reliable operation beyond 150 pF, external buffer stages are recommended to maintain timing margins and signal integrity.

How should unused inputs be handled on SN74HC158DR?

All unused inputs - including G, A/B, and any unconnected 1A–4B pins - must be tied to VCC or GND. Floating CMOS inputs cause increased ICC, erratic switching, and potential latch-up. TI recommends connecting unused inputs directly to supply rails using short traces to minimize noise coupling.