Texas Instruments SN74HC158DT

Overview

SN74HC158DT from Texas Instruments is a high-speed CMOS 2-line-to-4-line data selector/multiplexer with inverted outputs, operating across 2 V to 6 V supply range. It features 11 ns typical propagation delay at 6 V, ±6-mA output drive capability, and supports up to 15 LSTTL loads. Used in digital logic routing, bus selection, and address decoding circuits where signal inversion and low-power operation are required.

For engineers reviewing the SN74HC158DT datasheet, SN74HC158DT pinout, SN74HC158DT application, or SN74HC158DT equivalent, key selection criteria include its active-low strobe (G), dual-input per channel (A/B select), inverted Y outputs, SOIC-16 package footprint, and compatibility with HC logic families in mixed-voltage systems.

Technical Context

The SN74HC158DT implements four independent 2:1 multiplexer channels, each selecting between two inputs (A or B) based on the A/B control line and enabling all outputs simultaneously via the global active-low strobe (G). Its internal architecture includes inverters driving output gates, delivering true-inverted data at Y1–Y4.

All inputs accept standard CMOS voltage thresholds (VIH = 3.15 V min at VCC = 4.5 V; VIL = 1.35 V max), and outputs swing rail-to-rail with guaranteed VOH ≥ 3.7 V and VOL ≤ 0.33 V at 4.5 V/6 mA load. Input transition time limits (400–1000 ns) ensure reliable timing under slow-edge conditions.

Key Specifications

Pinout & Package

SN74HC158DT 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 lead pitch and gull-wing leads. Pin 1 is located at the top-left corner adjacent to the index marking.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 2-line-to-4-line multiplexer applications.

Compared with SN74HC158DT, SN74HC157DR provides identical functionality without inversion-reducing component count if polarity aligns, while SN74LV158ADT offers faster 3.3 V performance at the cost of 5 V interoperability and reduced noise margin.

Availability

SN74HC158DT is available at Aetrix Electronics and suitable for industrial control, test equipment, and legacy interface applications requiring stable component supply, long-term obsolescence management, and traceable sourcing.

Supply support for SN74HC158DT 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 90 years of innovation in industrial, automotive, and communications markets.

The SN74HC158DT belongs to TI's 74HC high-speed CMOS logic family, designed for pin-compatible upgrades of TTL-based systems while delivering lower power, wider voltage operation, and improved noise immunity.

FAQ

What is the function of the G (strobe) pin on the SN74HC158DT?

The G pin on the SN74HC158DT is an active-low strobe that globally enables or disables all four multiplexer outputs. When G is high, all Y outputs are forced high-impedance (Hi-Z); when G is low, outputs reflect the inverted selected input (A or B) per channel. This allows synchronized gating of data paths in time-critical systems without affecting internal logic states.

Does the SN74HC158DT support 3.3 V operation?

Yes, the SN74HC158DT fully supports 3.3 V operation within its specified 2 V to 6 V supply range. At VCC = 3.3 V, it delivers guaranteed VOH ≥ 2.4 V and VOL ≤ 0.36 V at 4 mA load, meets VIH/VIL thresholds scaled to VCC, and maintains 11 ns typical propagation delay - making it suitable for mixed-voltage 3.3 V/5 V system interfacing.

Can the SN74HC158DT replace a 74LS158 in an existing design?

Yes, the SN74HC158DT is a functional and pin-compatible replacement for the 74LS158 in most cases. It matches the same SOIC-16 footprint, logic function, and inverted output behavior, while offering lower ICC (80 µA vs ~15 mA), wider VCC range (2–6 V vs 4.75–5.25 V), and higher noise immunity. Verify timing margins due to faster tpd (11 ns vs ~20 ns) and ensure input transition times meet SN74HC158DT's 400–1000 ns limit.

What is the maximum capacitive load the SN74HC158DT can drive reliably?

The SN74HC158DT is characterized for CL = 50 pF and 150 pF loads in its datasheet. At VCC = 5 V, it maintains 11 ns typical tpd with 50 pF and 33 ns with 150 pF. Its ±6 mA output drive supports sustained operation into ≤100 pF loads at full speed; for >100 pF, derate switching frequency or add series termination to prevent ringing and ensure setup/hold compliance in downstream receivers.

Is the SN74HC158DT RoHS compliant?

Yes, the SN74HC158DT is RoHS compliant, as confirmed in TI's Package Option Addendum. It uses NiPdAu (NIPDAU) lead finish and carries a Level-1 moisture sensitivity rating (MSL-1, unlimited floor life at ≤30°C/60% RH), meeting JEDEC J-STD-020 requirements for lead-free reflow assembly up to 260°C peak temperature.