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Home > Products > Integrated Circuits (ICs) > Logic > Signal Switches, Multiplexers, Decoders

STMicroelectronics 74LCX257MTR

Name: 74LCX257MTR
Brand: STMicroelectronics
SKU: 74LCX257MTR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 74LCX257MTR

Manufacturer:: STMicroelectronics

Category:: Signal Switches, Multiplexers, Decoders

Package:: 16-SOIC (0.154", 3.90mm Width)

Datasheet:: 74LCX257MTR.pdf

Description:: IC MULTIPLEXER 4 X 2:1 16SO

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Product details

Overview

74LCX257MTR from STMicroelectronics is a low-voltage CMOS quad 2-channel multiplexer with 3-state outputs, 5V-tolerant I/O, and pin/function compatibility with standard 74-series 257 devices. It operates from 2.0V to 3.6V, delivers 6.0 ns max propagation delay at 3V, supports ±24 mA output drive, and features symmetrical output impedance and power-down protection on all I/O pins. It is used in voltage-translating data routing for 3.3V/5V mixed-signal systems such as PCI bus interfaces and FPGA I/O expansion.

For engineers reviewing the 74LCX257MTR datasheet, 74LCX257MTR pinout, 74LCX257MTR application, or 74LCX257MTR equivalent, key selection criteria include 5V-tolerant input/output capability, 3.3V-compatible propagation timing (tPLH ≅ tPHL), 3-state enable control (active-low OE), and guaranteed PCI bus-level drive at 24 mA under 3.0–3.6V supply conditions.

Technical Context

The 74LCX257 implements four independent non-inverting 2:1 multiplexers sharing common SELECT and active-low ENABLE inputs. Each channel selects between A and B inputs based on the logic level of SELECT, with outputs placed in high-impedance state when OE is high. All inputs and outputs are protected against ESD (>2000V HBM) and latch-up (>500 mA per JESD17).

It uses sub-micron C2MOS technology with double-layer metal wiring to achieve AC/ACT-family speed at 3.3V while consuming significantly less power. The device maintains data retention down to 1.5V and guarantees truth table operation across 1.5V–3.6V, with 5V tolerance enabling direct interfacing to legacy 5V logic without external level shifters.

Key Specifications

Parameter	Value and Actual Design Meaning
VCC Range	2.0 V to 3.6 V - Enables operation in modern low-voltage systems while retaining 1.5 V data retention during brownout.
tPD (max)	6.0 ns at VCC = 3.0 V - Matches 5V AC/ACT speed for seamless migration to 3.3V domains.
IOL / IOH	±24 mA at VCC = 3.0–3.6 V - Meets PCI bus drive requirements without external buffers.
5V Tolerance	Inputs and outputs withstand 0 V to 5.5 V - Allows direct connection to 5V controllers, sensors, or legacy peripherals.
Output Enable	Active-low OE with power-down protection - Ensures safe high-Z state during power sequencing or sleep modes.
Propagation Skew	≤1.0 ns (tOSLH/tOSHL) - Supports tightly synchronized multi-channel data routing in timing-critical paths.

Pinout & Package

74LCX257MTR is supplied in a 16-pin SOIC (Small Outline Integrated Circuit) package, tape-and-reel format (SOP), with 1.27 mm pitch and JEDEC MS-012AC compliant dimensions.

Pin/Terminal	Circuit Role	Design Meaning
1	SELECT	Common control input determining whether A or B data is routed to each Y output.
2,5,11,14	1A–4A	Four independent data inputs from Source A side of multiplexer pairs.
3,6,10,13	1B–4B	Four independent data inputs from Source B side of multiplexer pairs.
4,7,9,12	1Y–4Y	Four 3-state outputs, each driven by corresponding A/B selection and OE state.
15	OE	Active-low output enable controlling high-impedance state for all Y outputs simultaneously.
8	GND	Reference ground plane for logic and power integrity; decoupling capacitor connection point.
16	VCC	Primary 2.0–3.6 V supply rail; requires local ceramic decoupling near pin.

Key Features

Feature	Design Value
5V-tolerant I/O	Enables plug-and-play interoperability with 5V microcontrollers, FPGAs, and peripheral ICs without level-shifting circuitry.
Symmetrical output drive	\|IOH\| = IOL = 24 mA ensures matched rise/fall times and reduced signal distortion in bidirectional data paths.
Balanced propagation delays	tPLH ≅ tPHL minimizes duty cycle distortion in clocked or strobed data routing applications.
Power-down protection	Prevents current backflow and undefined states during partial power-down or hot-insertion scenarios.

Applications

PCI Bus Interface

FPGA I/O Expansion

Use Scenario: Routing address/data signals between 3.3V PCI slots and 5V legacy host bridges or add-in cards.

IC Role / Device Role / Timing Role: Quad 2:1 multiplexer providing voltage-transparent signal selection with guaranteed 24 mA drive at 3.3V.

Use Value: Eliminates need for discrete level translators while meeting PCI electrical compliance for signal integrity and fanout.

Use Scenario: Expanding limited FPGA I/O banks to support multiple sensor or memory interfaces with shared select lines.

IC Role / Device Role / Timing Role: Non-inverting data selector enabling dynamic reconfiguration of peripheral connections via FPGA-controlled SELECT/OE.

Use Value: Reduces FPGA pin count usage by 4× through time-multiplexed access to parallel peripherals without timing skew penalties.

Low-Power Embedded Controller

Mixed-Voltage Test Equipment

Use Scenario: Managing dual-source sensor inputs (e.g., analog front-end vs. digital diagnostic bus) in battery-powered IoT nodes.

IC Role / Device Role / Timing Role: Low-quiescent-current (10 µA ICC) multiplexer enabling selective activation of signal paths during sleep/wake cycles.

Use Value: Extends system runtime by gating unused analog/digital paths while maintaining fast wake-up response (<7 ns enable time).

Use Scenario: Signal routing in automated test fixtures handling both 3.3V DUTs and 5V instrumentation interfaces.

IC Role / Device Role / Timing Role: Voltage-agnostic switch supporting bidirectional signal pass-through with ESD-hardened I/O (2 kV HBM).

Use Value: Increases fixture reuse across product generations by eliminating manual jumper changes or adapter boards.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
74LVC257PW,118 (Nexperia)	Same 2.0–3.6 V range and 5V-tolerant I/O, but lower max output drive (±24 mA only at VCC ≥ 3.0 V; drops to ±12 mA at 2.7 V).	LVC version has slightly higher propagation skew (1.5 ns) and lacks explicit PCI bus guarantee at 24 mA.	Preferred for cost-sensitive industrial designs where PCI compliance is not required and tighter skew is acceptable.
SN74LVC257APW (TI)	Identical VCC range and 5V tolerance, but specified for −40°C to +125°C only (vs. −55°C to +125°C for LCX), and no JESD17 latch-up rating published.	Higher thermal grade than LCX in extended temperature variants, but no documented latch-up immunity >500 mA.	Recommended for automotive under-hood modules requiring wide-temp operation but not extreme latch-up robustness.

Compared with 74LVC257PW and SN74LVC257APW, the 74LCX257MTR offers superior latch-up immunity (>500 mA), broader operating temperature range (−55°C), and explicit PCI bus drive certification-making it optimal for mission-critical industrial and telecom infrastructure where reliability under transient stress is essential.

Availability

74LCX257MTR is available at Aetrix Electronics and suitable for PCI bus interface design, FPGA I/O expansion, low-power embedded controller signal routing, and mixed-voltage test equipment requiring stable component supply and long-term lifecycle support.

Supply support for 74LCX257MTR 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, power management, and microcontroller solutions with vertical manufacturing capabilities and broad IP portfolio.

The 74LCX logic family was engineered specifically for high-speed, low-power 3.3V system interfacing with legacy 5V environments-targeting PCI, embedded computing, and telecom infrastructure applications demanding robust voltage translation and ESD resilience.

FAQ

Is 74LCX257MTR compatible with 5V logic inputs while powered at 3.3V?

Yes. The device features fully 5V-tolerant inputs and outputs, allowing direct connection to 5V signal sources and loads while operating from a 2.0–3.6V supply. Input voltage range is −0.5V to +7.0V absolute maximum, and DC input voltage is guaranteed from 0 to 5.5V under recommended operating conditions.

What is the function of the OE pin, and how does it behave during power-down?

The OE (Output Enable) pin is active-low and places all four Y outputs in high-impedance state when driven high. During power-down, the device's built-in power-down protection prevents current backflow and maintains defined high-Z behavior even if VCC drops below operational threshold while inputs remain at 5V.

Does 74LCX257MTR support hot-swap or live-insertion scenarios?

Yes. Its power-down protection on all I/O pins, combined with 2 kV HBM ESD rating and latch-up immunity exceeding 500 mA (per JESD17), enables safe operation during hot-swap events in backplane or modular systems where boards may be inserted or removed while powered.

How does propagation delay matching (tPLH ≅ tPHL) benefit signal integrity in data routing?

Balanced propagation delays ensure minimal duty cycle distortion when routing clocked or strobed data streams. This preserves setup/hold timing margins in synchronous interfaces like PCI or parallel memory buses, reducing jitter accumulation and improving bit-error-rate performance in high-speed digital systems.

74LCX257MTR Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: 74LCX

Package/Case:: 16-SOIC (0.154", 3.90mm Width)

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Type:: Multiplexer

Circuit:: 4 x 2:1

Independent Circuits:: 1

Current - Output High, Low:: 24mA, 24mA

Voltage Supply Source:: Single Supply

Voltage - Supply:: 2V ~ 3.6V

Operating Temperature:: -55°C ~ 125°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 16-SO

74LCX257MTR FAQ

1.How can I place an order for 74LCX257MTR through Aetrix?

Please submit a Request for Quotation (RFQ) for 74LCX257MTR on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for 74LCX257MTR reliable?

The price and inventory of 74LCX257MTR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74LCX257MTR is usually 5 days.

3.What payment methods are accepted for 74LCX257MTR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74LCX257MTR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 74LCX257MTR?

74LCX257MTR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 74LCX257MTR order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for 74LCX257MTR?

For technical support, including 74LCX257MTR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74LCX257MTR requirements.

6.How does Aetrix verify that 74LCX257MTR is sourced from the original manufacturer or authorized distributors?

All 74LCX257MTR products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that 74LCX257MTR meets industry standards.

7.What is the process for return or replacement of 74LCX257MTR?

All 74LCX257MTR units undergo pre-shipment inspection (PSI). If there is an issue with 74LCX257MTR, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The 74LCX257MTR part is unused and in its original packaging.

Return procedure for 74LCX257MTR:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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