STMicroelectronics M74HCT08B1R

Overview

M74HCT08B1R from STMicroelectronics is a high-speed CMOS quad 2-input AND gate in 14-pin DIP package, featuring 13 ns typical propagation delay at VCC = 4.5 V, 4 mA minimum output drive (IOH/IOL), TTL-compatible input thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V), and 1 µA maximum quiescent ICC at 25°C - used for logic-level signal gating in industrial control backplanes.

For engineers reviewing the M74HCT08B1R datasheet, M74HCT08B1R pinout, M74HCT08B1R application, or M74HCT08B1R equivalent, this page delivers verified functional identity, validated DIP-14 pin mapping, confirmed DC/AC electrical specs across temperature ranges, and real-world interface compatibility with legacy TTL and NMOS systems.

Technical Context

The M74HCT08B1R implements four independent AND gates using silicon gate C2MOS technology with buffered outputs, enabling high noise immunity and stable rail-to-rail switching. Its two-stage internal architecture ensures balanced tPLH/tPHL delays and symmetrical output impedance (|IOH| = IOL ≥ 4 mA).

It operates within 4.5–5.5 V supply range and supports full industrial temperature range (−55°C to +125°C), with input rise/fall times up to 500 ns and guaranteed VIH/VIL margins for reliable interfacing with TTL outputs.

Key Specifications

Pinout & Package

Package: Plastic DIP-14 (Dual In-line Package), 0.3-inch body width, through-hole mounting compatible with standard 0.1-inch grid PCB layouts.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad 2-input AND gate applications.

Compared with SN74HCT08N and 74HCT08D, the M74HCT08B1R uniquely offers full −55°C to +125°C qualification in DIP-14, making it the only option for high-reliability through-hole deployments in extreme environments.

Availability

M74HCT08B1R is available at Aetrix Electronics and suitable for industrial PLC backplanes, automotive body control modules, and legacy TTL interface adapters requiring stable component supply over extended temperature ranges and long production lifecycles.

Supply support for M74HCT08B1R 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 microcontrollers, power ICs, analog chips, and logic families for industrial, automotive, and consumer applications.

The M74HCT08 belongs to ST's high-speed CMOS logic product line, engineered specifically to replace TTL devices while delivering lower power, higher noise immunity, and extended temperature resilience.

FAQ

Is M74HCT08B1R pin-compatible with 74LS08?

Yes - M74HCT08B1R has identical pinout and logic function to 74LS08, with TTL-compatible input thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V) and output drive capability sufficient to drive LS-TTL loads. No board changes are needed for direct replacement.

What is the maximum operating frequency supported by M74HCT08B1R?

The device does not specify a maximum clock frequency, but its 13 ns typical propagation delay at VCC = 4.5 V supports reliable operation in synchronous logic paths up to approximately 30 MHz, assuming minimal fanout and controlled trace impedance.

Does M74HCT08B1R require external pull-up or pull-down resistors on unused inputs?

No - all inputs include internal protection circuitry and have defined VIH/VIL thresholds, but floating inputs are not recommended. Unused inputs should be tied to VCC or GND to prevent noise-induced switching and minimize ICC variation.

Can M74HCT08B1R operate at 3.3 V supply?

No - the recommended VCC range is strictly 4.5 V to 5.5 V. At 3.3 V, VIH and VOH specifications are not guaranteed, and output drive strength degrades significantly; use 74HCT3G08 or similar 3.3 V–tolerant variants instead.