Texas Instruments SN74AHCT158PWR

Overview

SN74AHCT158PWR from Texas Instruments is a quadruple 2-line to 1-line data selector/multiplexer in TSSOP-16 package, operating at 4.5–5.5 V, featuring TTL-compatible inputs, inverted outputs, and a common strobe (G) input for output enable/disable control. It routes one of two 4-bit data sources to four outputs with propagation delays as low as 1 ns (typical) at 15-pF load, used in digital logic routing and address/data path selection in industrial control systems.

For engineers reviewing the SN74AHCT158PWR datasheet, SN74AHCT158PWR pinout, SN74AHCT158PWR application, or SN74AHCT158PWR equivalent, this page delivers verified electrical specs, validated pin functions, real-world use cases in bus multiplexing and signal routing, and confirmed drop-in alternatives - all grounded in TI's SCLS348J datasheet and official packaging documentation.

Technical Context

The SN74AHCT158PWR implements four independent 2:1 multiplexers sharing a single active-low strobe (G) input: when G = HIGH, all Y outputs are forced HIGH; when G = LOW, each Yn selects between An and Bn based on the A/B select line. All outputs are inverted - Yn = NOT[(A/B) ? An : Bn].

It uses advanced high-speed CMOS (AHCT) technology with TTL-voltage compatibility (VIH = 2 V, VIL = 0.8 V), latch-up immunity >250 mA (JESD 17), and ESD protection per JESD 22 (2000-V HBM, 200-V MM, 1000-V CDM). Its 16-pin TSSOP package supports surface-mount assembly with 0.65-mm lead pitch and 1.2-mm max height.

Key Specifications

Pinout & Package

TSSOP-16 package (PW), 4.4 mm × 5.0 mm footprint, 0.65 mm lead pitch, 1.2 mm max height, RoHS-compliant NiPdAu lead finish, MSL Level-1 (260°C peak reflow).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74AHCT158PWR, SN74AHCT157PWR offers identical timing and drive strength but non-inverted outputs - ideal for direct replacement where polarity alignment matters. SN74LVC157APWR trades 5-V compatibility for 3.3-V efficiency and faster propagation, requiring full voltage-domain validation before substitution.

Availability

SN74AHCT158PWR is available at Aetrix Electronics and suitable for industrial PLC I/O multiplexing, legacy bus address selection, FPGA glue logic, ATE signal routing, and digital test fixture design requiring stable component supply across extended temperature ranges.

Supply support for SN74AHCT158PWR 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 delivering analog, embedded processing, and logic solutions with over 50 years of process and reliability expertise.

The SN74AHCT158PWR belongs to TI's 74AHCT logic family - engineered for seamless 5-V TTL-to-CMOS interfacing in industrial, automotive, and communications infrastructure with guaranteed latch-up immunity and ESD robustness.

FAQ

What is the function of the A/B pin on the SN74AHCT158PWR?

The A/B pin is a common select line controlling all four 2:1 multiplexers. When A/B = LOW, each Y output reflects the corresponding A-input (1A–4A); when A/B = HIGH, each Y output reflects the corresponding B-input (1B–4B). This single-pin control eliminates the need for four separate select lines, reducing routing complexity and control logic overhead in the SN74AHCT158PWR design.

Does the SN74AHCT158PWR support 3.3-V input signals?

No - the SN74AHCT158PWR is designed for 4.5–5.5-V VCC operation and specifies VIH = 2.0 V minimum. While 3.3-V CMOS outputs may exceed this threshold, TI does not guarantee reliable recognition of 3.3-V logic HIGHs across temperature and process variation. For guaranteed 3.3-V compatibility, use SN74LVC157APWR instead of SN74AHCT158PWR.

What happens to the outputs of the SN74AHCT158PWR when the strobe (G) pin is HIGH?

When G = HIGH, all four Y outputs (1Y–4Y) are forced HIGH regardless of A/B state or data inputs. This high-impedance-equivalent behavior (though outputs are actively driven HIGH, not tri-stated) prevents bus contention and allows safe reconfiguration of upstream sources. This behavior is explicitly defined in the SN74AHCT158PWR function table and verified in Figure 1 timing waveforms.

Is the SN74AHCT158PWR pin-compatible with the SN74AHCT157PWR?

Yes - SN74AHCT158PWR and SN74AHCT157PWR share identical TSSOP-16 pinout, supply requirements, and control logic. The sole functional difference is output polarity: SN74AHCT158PWR provides inverted outputs (Y = NOT[select ? A : B]), while SN74AHCT157PWR provides true outputs (Y = select ? A : B). No PCB changes are required when substituting SN74AHCT157PWR for SN74AHCT158PWR if system logic accommodates the polarity inversion.

What is the maximum capacitive load the SN74AHCT158PWR can drive while maintaining specified timing?

The SN74AHCT158PWR's switching characteristics are specified at CL = 15 pF (max tPD = 7.5 ns) and CL = 50 pF (max tPD = 12 ns). Driving loads beyond 50 pF increases propagation delay nonlinearly and may violate setup/hold windows in high-speed systems. For loads >50 pF, TI recommends verifying timing margins using the SN74AHCT158PWR's Cpd = 11 pF and actual trace capacitance in the target layout.