STMicroelectronics M74HCT14TTR

Overview

M74HCT14TTR from STMicroelectronics is a high-speed CMOS hex Schmitt trigger inverter in TSSOP-14 package, featuring 0.7 V typical hysteresis at VCC = 4.5 V, 19 ns typical propagation delay, and ±4 mA symmetrical output drive. It interfaces TTL/NMOS logic with HCMOS systems and supports slow-rising/falling input signals in noise-prone industrial sensor conditioning and bus line reception.

For engineers reviewing the M74HCT14TTR datasheet, M74HCT14TTR pinout, M74HCT14TTR application, or M74HCT14TTR equivalent, key selection criteria include hysteresis voltage (VP/VN), propagation delay matching (tPLH ≅ tPHL), symmetrical output impedance (|IOH| = IOL ≥ 4 mA), and TSSOP-14 thermal derating (500 mW @ 65 °C).

Technical Context

The device implements six independent Schmitt-trigger inverters using silicon gate C2MOS technology, each with defined hysteresis (VH = VP − VN = 0.4–1.5 V) to reject input noise on slow-transition signals. Input protection diodes and static discharge circuits ensure robustness in industrial environments.

It operates across VCC = 4.5–5.5 V with guaranteed DC output levels (VOH ≥ 4.18 V at IO = −4 mA; VOL ≤ 0.26 V at IO = +4 mA) and maintains balanced propagation delays (tPLH/tPHL ≤ 38 ns max over −55 to +125 °C), enabling precise timing in clockless signal conditioning paths.

Key Specifications

Pinout & Package

TSSOP-14 package: 4.9 × 6.4 mm body, 0.65 mm pitch, 14-pin surface-mount with exposed pad not present; JEDEC MO-153 compliant; thermal resistance θJA ≈ 120 °C/W (standard PCB layout).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HCT14DR and 74LVC14APW, the M74HCT14TTR delivers optimal thermal performance in dense layouts (TSSOP-14), full 5 V TTL compatibility, and guaranteed hysteresis stability across −55 to +125 °C - making it the preferred choice for automotive and industrial embedded control.

Availability

M74HCT14TTR is available at Aetrix Electronics and suitable for industrial sensor interface, motor control feedback, and power supply sequencing monitor applications requiring stable component supply and long-term lifecycle support.

Supply support for M74HCT14TTR 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, sensors, and analog/mixed-signal devices for automotive, industrial, and consumer markets.

The M74HCT14 belongs to ST's legacy HCT logic family, engineered specifically for seamless interoperability between TTL, NMOS, and CMOS systems while maintaining low power and high noise immunity in harsh environments.

FAQ

Is M74HCT14TTR compatible with 3.3 V input signals?

No - M74HCT14TTR is designed for 5 V operation (VCC = 4.5–5.5 V). Its input thresholds (VP ≈ 1.4–2.1 V, VN ≈ 0.6–1.4 V at VCC = 5.5 V) are referenced to VCC, so 3.3 V logic may not reliably switch all devices. For 3.3 V systems, consider 74LVC14 or 74AHC14 instead.

What is the maximum capacitive load this device can drive?

The AC specifications are characterized at CL = 50 pF. While the output can source/sink ≥4 mA, driving >100 pF increases propagation delay nonlinearly and may cause ringing. For loads >75 pF, add a series resistor (22–47 Ω) near the output to dampen reflections.

Does M74HCT14TTR require external pull-up or pull-down resistors on unused inputs?

Yes - unused Schmitt inputs must be terminated to VCC or GND. Floating inputs cause increased ICC, unpredictable output states, and potential oscillation due to internal threshold ambiguity. A 10 kΩ pull-up to VCC is recommended for consistency with active-high logic conventions.

Can M74HCT14TTR operate at −55 °C?

Yes - the device is fully specified from −55 °C to +125 °C per its Recommended Operating Conditions table. Propagation delay increases to ≤45 ns at −55 °C (VCC = 4.5 V), and hysteresis remains functional, making it suitable for extended-temperature automotive and military applications.