Texas Instruments SN74HC158PW

Overview

SN74HC158PW from Texas Instruments is a 4-bit dual-input data selector/multiplexer with inverted outputs, operating across 2 V to 6 V supply range. It features ±6-mA output drive at 5 V, typical propagation delay of 11 ns (VCC = 6 V, CL = 50 pF), and supports up to 15 LSTTL loads - used in digital logic routing, address/data bus selection, and control signal arbitration in industrial microcontroller interfaces.

For engineers reviewing the SN74HC158PW datasheet, SN74HC158PW pinout, SN74HC158PW application, or SN74HC158PW equivalent, key selection considerations include its TSSOP-16 package, active-low strobe (G) control, A/B select logic for source routing, and guaranteed CMOS-level input thresholds across full voltage range.

Technical Context

The SN74HC158PW implements four independent 2:1 multiplexer channels, each selecting between two complementary inputs (A and B) under shared A/B select line and global active-low enable (G). All outputs are inverted - Y = NOT[(A·G·A/B) + (B·G·NOT(A/B))].

Its HC-series CMOS architecture delivers rail-to-rail output swing, low static current (≤80 µA ICC max), and input leakage ≤1 µA, enabling direct interfacing with TTL and other 5-V logic families while maintaining compatibility down to 2-V operation for mixed-supply systems.

Key Specifications

Pinout & Package

TSSOP-16 package (PW), 4.4 mm × 5.0 mm body, 0.65 mm lead pitch, 1.2 mm max height, exposed pad not present, RoHS-compliant NiPdAu finish, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HC158PW, SN74HC157PW offers identical form-factor and electrical behavior except output polarity, while SN74LVC157APW trades wider voltage tolerance for superior 3.3-V performance - making the HC158PW optimal for mixed-voltage industrial systems needing inversion and 5-V compatibility.

Availability

SN74HC158PW is available at Aetrix Electronics and suitable for industrial control logic, microcontroller peripheral multiplexing, and legacy bus interface applications requiring stable component supply and long-term lifecycle support.

Supply support for SN74HC158PW 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 for industrial, automotive, and communications markets.

The SN74HC158PW belongs to TI's 74HC logic family - designed for high-noise-immunity, low-power digital signal routing in industrial automation, test equipment, and legacy system upgrades.

FAQ

What is the function of the G (strobe) pin on the SN74HC158PW?

The G pin is an active-low enable input: when G = HIGH, all four outputs (1Y–4Y) are forced HIGH regardless of A/B or data inputs; when G = LOW, the device performs normal 2:1 multiplexing per channel. This allows synchronous gating of all outputs using a single control signal - essential for time-critical bus arbitration in the SN74HC158PW.

Does the SN74HC158PW support 3.3-V operation?

Yes, the SN74HC158PW operates over 2 V to 6 V, fully supporting 3.3-V systems. At VCC = 3.3 V, it maintains guaranteed VIH ≥ 2.0 V and VIL ≤ 1.3 V, with typical tpd ≈ 15 ns (CL = 50 pF), making it compatible with standard 3.3-V microcontrollers and FPGAs without level translation - a key feature of the SN74HC158PW.

Are unused inputs on the SN74HC158PW required to be terminated?

Yes, all unused inputs (including A/B, G, and any unconnected 1A–4B) must be tied to VCC or GND. Floating CMOS inputs can cause increased ICC, oscillation, or latch-up due to undefined threshold crossing - TI explicitly mandates this in the SN74HC158PW datasheet (SCBA004 application report) to ensure stable operation.

What is the thermal resistance (θJA) of the SN74HC158PW in its TSSOP package?

The SN74HC158PW in TSSOP-16 (PW) package has a specified junction-to-ambient thermal resistance (θJA) of 108°C/W under JEDEC JESD51-7 conditions. This value assumes standard 2-layer board layout with no copper pour; actual thermal performance improves significantly with PCB copper heatsinking - critical for sustained operation in enclosed industrial enclosures using the SN74HC158PW.

Can the SN74HC158PW replace the SN74LS158 in existing designs?

Yes, the SN74HC158PW is a functional and pin-compatible upgrade for SN74LS158, offering identical pinout, logic function, and DC characteristics - but with lower power (80 µA vs. ~20 mA ICC), wider voltage range (2–6 V vs. 4.75–5.25 V), and improved noise immunity. No PCB changes are needed, though timing analysis should confirm tpd compatibility - a validated drop-in replacement for the SN74HC158PW.