Texas Instruments SN74AHCT158DRG4

Overview

SN74AHCT158DRG4 from Texas Instruments is a quadruple 2-line to 1-line data selector/multiplexer IC operating at 4.5 V to 5.5 V, featuring TTL-compatible inputs, active-low strobe (G) control, inverted outputs, and 16-pin SOIC packaging. It routes one of two 4-bit input sources to four outputs based on the A/B select line, used in digital logic routing, address decoding, and bus multiplexing in industrial control systems.

For engineers reviewing the SN74AHCT158DRG4 datasheet, SN74AHCT158DRG4 pinout, SN74AHCT158DRG4 application, or SN74AHCT158DRG4 equivalent, key selection criteria include its 7.5 ns max propagation delay (A/B → Y, CL = 15 pF), ±8 mA output drive, latch-up immunity >250 mA per JESD 17, and compatibility with 5-V TTL and CMOS logic families.

Technical Context

The SN74AHCT158DRG4 implements four independent 2:1 multiplexers sharing a common strobe (G) and select (A/B) input. Each channel selects between inputs A and B and drives an inverted output Y, with G enabling all outputs when low and forcing high-impedance (logic-high) when high.

Its architecture supports TTL-voltage-level inputs (VIH = 2 V, VIL = 0.8 V) while maintaining CMOS-compatible output swing (VOH ≥ 3.8 V, VOL ≤ 0.44 V at VCC = 4.5 V, IOL = 8 mA). Propagation delays are specified for three signal paths: data (A/B → Y), select (A/B → Y), and strobe (G → Y), with worst-case values up to 10 ns under 50-pF load conditions.

Key Specifications

Pinout & Package

SN74AHCT158DRG4 is housed in a 16-pin SOIC (D) package with 1.27-mm pitch, 10.3-mm body width, and 1.75-mm maximum height. Pin 1 is located at the top-left corner adjacent to the index notch.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 4-bit 2:1 multiplexer applications.

Compared with SN74AHCT158DRG4, SN74AHCT157DR offers identical timing and drive strength but delivers non-inverted outputs-critical for polarity-sensitive interfaces-while 74LVC157APW enables higher-speed, lower-voltage operation at the cost of 5-V compatibility and requires PCB redesign due to different package dimensions and voltage domain isolation.

Availability

SN74AHCT158DRG4 is available at Aetrix Electronics and suitable for industrial automation, test equipment, and legacy microcontroller interfacing requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant sourcing.

Supply support for SN74AHCT158DRG4 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 SN74AHCT158DRG4 belongs to TI's AHCT logic family, designed specifically to bridge 5-V TTL and CMOS systems with guaranteed TTL-input compatibility, robust ESD/latch-up performance, and predictable propagation timing for deterministic digital control.

FAQ

What is the function of the G (strobe) pin on the SN74AHCT158DRG4?

The G pin on the SN74AHCT158DRG4 is an active-low strobe input that globally enables or disables all four multiplexer channels. When G is high, all four outputs (1Y–4Y) are forced high regardless of A/B or data inputs. When G is low, the device routes selected inputs (A or B per channel) to outputs with inversion. This enables synchronized gating of 4-bit data words in timing-critical control logic, and is essential for bus arbitration and conditional signal routing in the SN74AHCT158DRG4.

Does the SN74AHCT158DRG4 support 3.3-V input signals?

No, the SN74AHCT158DRG4 does not reliably accept 3.3-V inputs as valid logic levels. Its input thresholds are TTL-compatible: VIH = 2.0 V minimum and VIL = 0.8 V maximum at VCC = 4.5–5.5 V. While a 3.3-V high signal exceeds VIH, noise margins shrink significantly, risking misreads in noisy environments. For guaranteed interoperability with 3.3-V systems, level-shifting circuitry or a 3.3-V–compatible multiplexer like the 74LVC157APW is required alongside the SN74AHCT158DRG4.

Can the SN74AHCT158DRG4 be used in place of the SN74AHCT157DR?

The SN74AHCT158DRG4 and SN74AHCT157DR share identical pinouts, timing, supply specs, and functionality except for output polarity: SN74AHCT158DRG4 provides inverted outputs (Y = NOT(selected input)), while SN74AHCT157DR provides true outputs (Y = selected input). They are not functionally interchangeable without adjusting downstream logic. If your design relies on inverted outputs, SN74AHCT158DRG4 is correct; if it expects true outputs, SN74AHCT157DR must be used instead.

What is the maximum capacitive load the SN74AHCT158DRG4 can drive while maintaining specified timing?

The SN74AHCT158DRG4 is characterized for timing performance up to 50 pF total load capacitance, with propagation delays specified at both 15 pF and 50 pF (e.g., tPLH/tPHL ≤ 12 ns for A/B → Y at CL = 50 pF). Exceeding 50 pF increases delay nonlinearly and may cause setup/hold violations in high-speed systems. For loads >50 pF, buffer amplification or reduced clock rates are recommended to maintain timing integrity in the SN74AHCT158DRG4.

Is the SN74AHCT158DRG4 RoHS compliant and lead-free?

Yes, the SN74AHCT158DRG4 is RoHS compliant and features a lead-free NIPDAU (nickel/palladium/gold) terminal finish. Per TI's packaging documentation, it carries a Level-1 moisture sensitivity rating with unlimited floor life at ≤30°C/60% RH, and is qualified for peak reflow temperatures up to 260°C. This makes the SN74AHCT158DRG4 suitable for modern lead-free PCB assembly processes without special handling requirements.