STMicroelectronics M74HC266B1R

Overview

M74HC266B1R from STMicroelectronics is a high-speed CMOS quad exclusive-NOR gate with open-drain outputs, fabricated using silicon gate C2MOS technology. It operates across 2V–6V supply, delivers 10ns typical propagation delay at 6V, draws ≤1µA quiescent current at 25°C, and features 28% VCC noise immunity. It serves in level-shifting logic interfaces and wired-AND bus configurations in industrial control panels.

For engineers reviewing the M74HC266B1R datasheet, M74HC266B1R pinout, M74HC266B1R application, or M74HC266B1R equivalent, key selection criteria include open-drain output drive capability (5.2mA sink at 6V), wide temperature range (−55°C to +125°C), input hysteresis for noise rejection, and DIP-14 package compatibility with legacy 74-series layouts.

Technical Context

The device implements four independent EXNOR gates, each with open-drain output requiring external pull-up for logic HIGH assertion. Its C2MOS process enables low ICC while maintaining rail-to-rail input voltage tolerance (0 to VCC) and robust ESD protection on all pins.

Propagation delay varies with supply: 10ns typ. at VCC = 6V, 18ns typ. at 4.5V, and 90ns max. at 2V under 1kΩ load. Output transition time (tTHL) is 7ns typ. at 6V, supporting reliable timing in asynchronous wired-logic networks.

Key Specifications

Pinout & Package

Package: Plastic DIP-14 (dual in-line package, 0.3" width, through-hole mount).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad EXNOR gate applications.

Compared with SN74HC266N and CD74HC266E, the M74HC266B1R offers identical logic behavior and timing but is optimized for European industrial qualification standards and ships in ST-specific tube packaging - critical for traceability in regulated OEM production.

Availability

M74HC266B1R is available at Aetrix Electronics and suitable for industrial PLC I/O expansion, automotive body control modules, legacy system voltage translation, and test equipment signal conditioning requiring stable component supply across extended temperature ranges.

Supply support for M74HC266B1R 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 automotive, industrial, and consumer markets.

The M74HC266B1R belongs to ST's high-speed HC logic family, engineered for interoperability with legacy TTL systems while delivering CMOS power efficiency and noise resilience in harsh environments.

FAQ

Can M74HC266B1R drive an LED directly?

No - its open-drain outputs can only sink current, not source it. To drive an LED, connect the anode to VCC (≤6V) and cathode to an output pin via a current-limiting resistor. At 6V and 5.2mA sink, a 680Ω resistor yields ~5.2mA forward current, suitable for indicator use without exceeding absolute max ratings.

Is external pull-up required for all outputs?

Yes - every output (Pins 3, 4, 10, 11) is open-drain and requires an external pull-up resistor to define the HIGH logic state. Typical values range from 4.7kΩ (for speed) to 100kΩ (for ultra-low power), selected based on bus capacitance and rise-time requirements per I²C or custom wired-AND implementation.

Does M74HC266B1R support mixed-voltage operation between inputs and VCC?

No - all inputs must remain within 0V to VCC. Applying 5V to an input while VCC = 3.3V violates Absolute Maximum Rating VI = −0.5V to VCC + 0.5V and risks latch-up or permanent damage. Use level translators for cross-voltage signal routing.

What is the maximum capacitive load CL for guaranteed timing performance?

AC specifications (e.g., tPD = 10ns typ.) are characterized at CL = 50pF. Driving >100pF increases propagation delay nonlinearly - e.g., at 100pF and 6V, tPD degrades to ~15ns. For heavy loads, add a buffer stage or reduce trace length and parallel capacitance to maintain timing margins.