STMicroelectronics 74ACT157MTR

Overview

74ACT157MTR from STMicroelectronics is a high-speed CMOS quad 2-channel non-inverting multiplexer with pin- and function-compatibility to standard 74-series 157 logic. It features 5.5 ns typical propagation delay at 5 V, ±24 mA symmetrical output drive, 4.5–5.5 V operating range, and 2 kV ESD immunity. It routes A/B data inputs to Y outputs under common SELECT/STROBE control in industrial control and digital instrumentation systems.

For engineers reviewing the 74ACT157MTR datasheet, 74ACT157MTR pinout, 74ACT157MTR application, or 74ACT157MTR equivalent, key selection criteria include propagation delay matching (tPLH ≅ tPHL), 50 Ω transmission line driving capability, TTL-compatible input thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V), and latch-up immunity for mixed-voltage interface designs.

Technical Context

The device implements four independent 2:1 multiplexers sharing a common SELECT line and active-high STROBE enable. When STROBE = HIGH, all Y outputs are forced LOW regardless of SELECT state - enabling synchronized channel blanking. SELECT determines whether A-inputs (pins 2,5,11,14) or B-inputs (pins 3,6,10,13) pass through to corresponding Y outputs (pins 4,7,9,12).

Designed for direct interfacing between HCMOS, TTL, NMOS, and CMOS logic families, it guarantees VIH ≥ 2.0 V and VIL ≤ 0.8 V across full temperature range (−55°C to +125°C), with symmetrical |IOH| = |IOL| ≥ 24 mA drive strength and balanced tPLH/tPHL delays within ±0.5 ns variation.

Key Specifications

Pinout & Package

TSSOP-16 package (4.9 × 6.4 mm body, 0.65 mm pitch), lead-free, RoHS-compliant, moisture sensitivity level 1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74ACT157DR and 74LCX157MTCX, the 74ACT157MTR uniquely combines TSSOP-16 compactness, full 5 V operation, and guaranteed 5.5 ns propagation delay - making it optimal for high-density industrial control boards requiring legacy 74-series compatibility and robust 50 Ω drive.

Availability

74ACT157MTR is available at Aetrix Electronics and suitable for industrial PLC I/O multiplexing, digital test equipment signal routing, and automotive body control module bus arbitration requiring stable component supply and long-term lifecycle support.

Supply support for 74ACT157MTR 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, specializing in automotive, industrial, and power discrete solutions with vertical manufacturing capabilities.

The 74ACT logic family targets high-speed, low-power 5 V digital interface applications where TTL compatibility, ESD robustness, and precise timing predictability are critical - especially in legacy system upgrades and harsh-environment controls.

FAQ

Is the 74ACT157MTR pin-compatible with older 74LS157 devices?

Yes - it uses identical pin numbering and logic function mapping: SELECT (pin 1), A/B inputs (pins 2–3,5–6,10–13), Y outputs (pins 4,7,9,12), STROBE (pin 15), GND (pin 8), and VCC (pin 16). No PCB redesign is needed for drop-in replacement in existing 74LS157 layouts.

What is the maximum recommended load capacitance for stable 5.5 ns propagation delay?

The 5.5 ns typical tPD is specified with CL = 50 pF and RL = 500 Ω. For loads exceeding 50 pF, propagation delay increases linearly - e.g., at 100 pF, tPD degrades to ~7.2 ns. Keep trace capacitance below 15 pF and use point-to-point routing to maintain sub-6 ns timing.

Does the STROBE input override the SELECT signal unconditionally?

Yes - when STROBE = HIGH, all four Y outputs are forced LOW regardless of SELECT state or A/B input values. This provides hardware-level channel disable independent of data path control, enabling safe bus isolation during reset or fault conditions.

Can the 74ACT157MTR operate reliably at VCC = 4.5 V across −55°C to +125°C?

Yes - the datasheet guarantees full functionality including VIH ≥ 1.5 V, VOL ≤ 0.5 V, and tPD ≤ 11.3 ns across the entire industrial temperature range at VCC = 4.5 V, validated per STMicroelectronics' AEC-Q100 stress testing protocols.