STMicroelectronics 74AC14MTR

Overview

74AC14MTR from STMicroelectronics is a high-speed CMOS hex Schmitt trigger inverter with 6 independent buffered inverters, 4.5 ns typical propagation delay at 5 V, ±24 mA output drive, and 2 V to 6 V operating voltage range. It serves as noise-immune signal conditioning and waveform shaping for slow-rising digital inputs in industrial control interfaces.

For engineers reviewing the 74AC14MTR datasheet, 74AC14MTR pinout, 74AC14MTR application, or 74AC14MTR equivalent, key selection criteria include hysteresis voltage (1.2 V typ. at 5 V), transmission-line driving capability (50 Ω), symmetrical output impedance, latch-up immunity, and TSSOP-14 package compatibility with space-constrained PCB layouts.

Technical Context

The device implements six independent Schmitt-trigger input stages followed by CMOS buffer outputs, enabling stable switching on noisy or slowly transitioning signals. Each gate features hysteresis (V_t+ = 3.9 V, V_t− = 1.1 V at V_CC = 5.5 V), ensuring clean logic transitions without chatter.

Its sub-micron C2MOS process delivers low ICC (4 µA max at 25°C) and high noise immunity, while symmetrical output drive (|I_OH| = |I_OL| = 24 mA min) supports balanced rise/fall times and 50 Ω transmission-line termination without external resistors.

Key Specifications

Pinout & Package

TSSOP-14 (Thin Shrink Small Outline Package), 4.4 mm × 5.0 mm body, 0.65 mm pitch, 1.2 mm height - optimized for automated SMT assembly and high-density routing.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar Schmitt-trigger inverter applications.

Compared with SN74AC14DR and 74LVC14APW, the 74AC14MTR offers optimal trade-off of 5 V robustness, TSSOP-14 miniaturization, and industry-standard Schmitt performance-making it preferred for industrial automation PCBs where density and noise immunity are jointly critical.

Availability

74AC14MTR is available at Aetrix Electronics and suitable for industrial sensor interfaces, RS-485 node conditioning, and microcontroller reset circuits requiring stable component supply across extended temperature ranges (–55°C to +125°C).

Supply support for 74AC14MTR 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 silicon solutions for automotive, industrial, and power management applications.

The 74AC logic family targets high-speed, low-power digital interface and signal conditioning in harsh-environment systems, emphasizing noise immunity, wide supply tolerance, and robust ESD/latch-up performance.

FAQ

What is the maximum recommended input rise/fall time for reliable Schmitt-trigger operation?

The 74AC14MTR guarantees correct operation with input transitions as slow as 100 ns/V (e.g., 500 ns for 5 V swing), per its hysteresis design and internal stage buffering. This allows direct connection to RC-filtered switches, thermistor comparators, or long cables without added slew-rate limiting.

Can 74AC14MTR drive a 50 Ω coaxial cable directly?

Yes - its ±24 mA output drive and symmetrical impedance enable direct 50 Ω source termination. When configured with output pin series-connected to cable, it achieves near-perfect impedance matching without external resistors, minimizing reflections at frequencies up to ~100 MHz.

Is the 74AC14MTR pin-compatible with older 74HC14 devices?

Yes - it maintains identical pinout, logic function, and DC voltage levels with 74HC14, but offers faster propagation (4.5 ns vs. 20 ns typ.), higher drive strength (24 mA vs. 4 mA), and improved noise immunity due to tighter hysteresis control and C2MOS process enhancements.

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

No - all inputs are internally protected and have no DC path to V_CC or GND. However, floating inputs must be avoided: tie unused inputs to V_CC or GND to prevent increased ICC and potential oscillation due to noise coupling into high-impedance Schmitt thresholds.