Texas Instruments CD74AC158M

Overview

CD74AC158M from Texas Instruments is a quadruple 2-line to 1-line data selector/multiplexer with inverted outputs, designed for 1.5-V to 5.5-V operation, ±24-mA output drive, and balanced propagation delays. It features a common strobe (G) input that disables all outputs when high and routes selected 4-bit data when low - used in digital logic routing, address/data bus selection, and signal path control in industrial controllers.

For engineers reviewing the CD74AC158M datasheet, CD74AC158M pinout, CD74AC158M application, or CD74AC158M equivalent, key selection criteria include VCC operating range (1.5–5.5 V), output drive strength (±24 mA), propagation delay at 5 V (2–8 ns), ESD rating (2 kV per MIL-STD-883), and SOIC-16 package compatibility with legacy AC logic families.

Technical Context

The CD74AC158M implements four independent 2:1 multiplexers sharing one active-low strobe (G) and one select line (A/B), each producing inverted output (Y). Its CMOS process ensures SCR-latchup resistance and balanced noise immunity at 30% of VCC.

It operates across –55°C to +125°C with guaranteed switching performance at 1.5 V, 3.3 V, and 5 V supply levels; propagation delays are specified separately for A/B inputs (3.2–12.9 ns at 5 V), data inputs (A or B), and strobe (G) - enabling precise timing analysis in synchronous logic systems.

Key Specifications

Pinout & Package

CD74AC158M is housed in a 16-pin SOIC (D) package with standard 1.27-mm pitch, 10.2-mm body width, and RoHS-compliant NiPdAu lead finish (MSL Level-1).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74AC158N and CD74HC158M, the CD74AC158M delivers superior output drive and speed within the same SOIC-16 footprint, making it optimal for industrial control and test equipment where signal integrity and thermal performance are prioritized.

Availability

CD74AC158M is available at Aetrix Electronics and suitable for industrial PLC I/O expansion, digital test equipment signal routing, and legacy system bus interface applications requiring stable component supply across extended temperature ranges.

Supply support for CD74AC158M 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 CD74AC158M belongs to TI's Advanced CMOS (AC) logic family, engineered for high-speed, low-power operation across wide voltage and temperature ranges - targeting robust digital control and signal routing in harsh environments.

FAQ

What is the maximum operating temperature range for CD74AC158M?

The CD74AC158M is fully specified from –55°C to +125°C, with electrical characteristics guaranteed across this full industrial and extended automotive temperature range. This includes validated switching performance, output drive capability, and noise immunity at both extremes - making CD74AC158M suitable for under-hood automotive modules and downhole oilfield electronics where ambient temperatures exceed 100°C.

Does CD74AC158M require external pull-up or pull-down resistors on unused inputs?

Yes - all unused inputs of CD74AC158M must be held at either VCC or GND to prevent floating states that could cause excessive ICC, logic contention, or unpredictable output behavior. This requirement is explicitly stated in TI's recommended operating conditions and applies regardless of whether the input is A/B, G, or any data line; CD74AC158M does not include internal weak pull-ups or pull-downs.

Is CD74AC158M pin-compatible with CD74HC158M?

Yes - CD74AC158M and CD74HC158M share identical pin assignments, SOIC-16 package dimensions, and functional block diagram. However, they differ electrically: CD74AC158M offers ±24-mA drive and faster propagation (2–8 ns at 5 V), while CD74HC158M provides only ±5.2-mA drive and slower timing (16 ns typical). The pinout match enables drop-in replacement only if drive strength and speed requirements are verified.

What is the meaning of "inverted output" in CD74AC158M's function table?

"Inverted output" means that CD74AC158M produces logically complemented data at each Y pin: when input A is selected and A = HIGH, output Y = LOW; when B is selected and B = LOW, Y = HIGH. This inversion is inherent to the internal gate structure and eliminates the need for external inverters in active-low enable schemes - a key design feature confirmed in the function table and logic diagram of CD74AC158M.

Can CD74AC158M operate reliably at 1.8 V supply voltage?

Yes - CD74AC158M is explicitly rated for 1.5-V to 5.5-V operation, and its recommended operating conditions include full functionality at 1.8 V. At this voltage, VIH is 1.26 V and VIL is 0.54 V (30% of VCC), providing adequate noise margin. Switching characteristics are characterized down to 1.5 V, confirming CD74AC158M's suitability for low-voltage portable and IoT edge-node designs where supply rails are scaled below 3.3 V.