STMicroelectronics 74AC157MTR

Overview

74AC157MTR from STMicroelectronics is a quad 2-channel non-inverting CMOS multiplexer with common SELECT and STROBE inputs, operating from 2V to 6V supply, delivering 4ns typical propagation delay at 5V, ±24mA symmetrical output drive, and 2kV ESD immunity. It routes A/B data pairs to Y outputs in industrial control logic, digital test equipment, and address/data bus selection.

For engineers reviewing the 74AC157MTR datasheet, 74AC157MTR pinout, 74AC157MTR application, or 74AC157MTR equivalent, key selection criteria include its 50Ω transmission line driving capability, latch-up immunity, balanced tPLH/tPHL delays, and compatibility with legacy 74-series logic timing and footprint.

Technical Context

The device implements four independent 2:1 multiplexers sharing one active-low STROBE and one SELECT input; when STROBE is high, all Y outputs are forced low regardless of SELECT state. Its C2MOS sub-micron silicon gate process enables rail-to-rail input voltage tolerance (0–VCC) and low quiescent ICC ≤ 4µA at 25°C.

Propagation delays are matched across signal paths (A→Y, B→Y, SELECT→Y, STROBE→Y), with tPLH ≅ tPHL specified down to –55°C. Output impedance is symmetrical (|IOH| = IOL ≥ 24mA), supporting clean 50Ω line termination without external resistors.

Key Specifications

Pinout & Package

TSSOP-16 package: 4.9mm × 6.4mm body, 0.65mm pitch, 1.1mm height, lead-free and RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 74HC157D and SN74ACT157DR, the 74AC157MTR uniquely combines 4ns speed, 24mA drive, and 2kV ESD in TSSOP-16-making it optimal for high-reliability, high-speed industrial signal routing where both timing margin and ruggedness are mandatory.

Availability

74AC157MTR is available at Aetrix Electronics and suitable for industrial PLC I/O expansion, digital test equipment signal routing, and embedded system address/data bus switching requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for 74AC157MTR 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, designing and manufacturing analog, digital, and mixed-signal ICs for industrial, automotive, and consumer markets.

The 74AC logic family targets high-speed, low-power digital interface and signal-routing applications where performance, noise immunity, and legacy compatibility are essential.

FAQ

Is the 74AC157MTR pin-compatible with standard 74LS157 devices?

Yes - it uses identical TSSOP-16 pinout and function mapping, including SELECT (pin 1), STROBE (pin 15), and Y outputs (pins 4,7,9,12). No PCB redesign is needed for migration from 74LS157, though VCC range expands from 4.75–5.25V to 2–6V and drive capability increases significantly.

What is the maximum recommended load capacitance for reliable 4ns propagation performance?

The 4ns typical tPD is characterized at CL = 50pF. For loads exceeding 50pF, propagation delay increases linearly - e.g., at 100pF, tPD degrades to ~6.5ns. Maintain trace lengths <5cm and avoid stubs to preserve signal integrity at >50MHz operation.

Does the STROBE input override the SELECT input unconditionally?

Yes - when STROBE is high, all four Y outputs are forced low regardless of SELECT state or A/B input values. This enables synchronous blanking during bus handshaking or fault isolation, and is electrically guaranteed across the full –55°C to +125°C temperature range.

Can the 74AC157MTR operate reliably at 3.3V with 5V-tolerant inputs?

Yes - inputs tolerate 0–VCC, so at VCC = 3.3V, they accept 0–3.3V logic levels. However, the part does not support 5V-tolerant inputs: applying >3.3V to any input while VCC = 3.3V violates absolute maximum ratings and risks damage.