onsemi MC74AC14NG

Overview

MC74AC14NG from onsemi is a hex Schmitt-trigger inverter IC designed for signal conditioning and noise-immune digital interface applications. It features six independent inverters with hysteresis (typ. 1.0 V at 5.0 V), TTL-compatible input thresholds (V_t+ = 3.2 V, V_t− = 0.9 V @ V_CC = 4.5 V), ±24 mA output drive, and operation across 2.0–6.0 V supply range. It is used in clock shaping, debouncing mechanical switches, and cleaning slow-rising sensor signals in industrial control systems.

For engineers reviewing the MC74AC14NG datasheet, pinout, applications, or equivalent options, key selection considerations include its CMOS-input Schmitt trigger behavior, 7.0 ns typical propagation delay (V_CC = 5.0 V, C_L = 50 pF), SOIC-14 Pb-free package, −40°C to +85°C operating range, and absence of TTL-input compatibility (distinguishing it from MC74ACT14).

Technical Context

The MC74AC14NG implements six independent Schmitt-trigger inverter stages using high-performance silicon-gate CMOS technology. Each stage provides hysteresis determined by internal transistor ratios-ensuring stable switching thresholds insensitive to temperature and supply voltage variation. Its input structure accepts standard CMOS logic levels (not TTL), with guaranteed V_t+/V_t− separation of ≥0.4 V over full temperature and voltage range.

Output stages are fully buffered CMOS drivers capable of sourcing/sinking 24 mA per channel under DC conditions, supporting fan-out to multiple CMOS loads. The device operates without external components and requires no biasing-only V_CC and GND connections-making it suitable for direct integration into level-shifting and waveform-squaring functions within mixed-signal subsystems.

Key Specifications

Pinout & Package

MC74AC14NG is housed in a 14-lead SOIC (Small Outline Integrated Circuit) package, case 751A, with 1.27 mm pitch, Pb-free finish, and JEDEC-standard footprint. Dimensions: 8.75 × 3.90 × 1.75 mm (L × W × H). Pin 1 marked by notch or beveled corner.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LV14APWR and 74HC14D,653, the MC74AC14NG delivers superior noise immunity (1.0 V hysteresis vs. 0.8 V typical), higher output current (24 mA vs. 12 mA or 4 mA), and faster propagation (7 ns vs. 10 ns or 105 ns), making it optimal for industrial switch debouncing and clock-shaping where reliability and timing precision are critical.

Availability

MC74AC14NG is available at Aetrix Electronics and suitable for industrial control panels, factory automation interfaces, and embedded sensor signal conditioning requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for MC74AC14NG 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

onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power management, analog, logic, and discrete devices for automotive, industrial, cloud, and IoT applications.

The MC74AC14NG belongs to onsemi's 74AC logic family - engineered for high-speed, low-noise digital interfacing in harsh industrial environments where signal integrity and thermal stability are essential.

FAQ

What is the maximum supply voltage rating for MC74AC14NG?

The MC74AC14NG has an absolute maximum DC supply voltage (V_CC) of +6.5 V, but its recommended operating range is 2.0 V to 6.0 V. Operating continuously above 6.0 V risks exceeding internal oxide breakdown limits and may cause permanent damage. For reliable long-term use in industrial applications, maintain V_CC ≤ 6.0 V with proper decoupling, and always verify actual rail voltage under load before deploying MC74AC14NG in production systems.

Does MC74AC14NG support TTL-level inputs?

No, MC74AC14NG does not support TTL-level inputs. It is a CMOS-input Schmitt-trigger device with V_t+ ≈ 3.2 V and V_t− ≈ 0.9 V at V_CC = 4.5 V - incompatible with standard TTL's 2.0 V VIH threshold. For TTL-compatible operation, use MC74ACT14 instead. Attempting to drive MC74AC14NG with 3.5 V TTL outputs may result in marginal or undefined switching behavior, especially over temperature. Always validate input voltage thresholds against your source driver when using MC74AC14NG.

What is the typical propagation delay of MC74AC14NG at 5 V supply?

The typical propagation delay (t_PLH and t_PHL) of MC74AC14NG is 7.0 ns when operated at V_CC = 5.0 V with a 50 pF capacitive load and ambient temperature of +25°C. This value is confirmed in the AC Characteristics table on page 3 of the official onsemi datasheet. At worst-case conditions (−40°C to +85°C, V_CC = 4.5 V), the maximum specified delay is 11.0 ns - critical for timing-critical applications like clock division or synchronous debouncing. Designers should use this 11.0 ns worst-case figure for setup/hold analysis when integrating MC74AC14NG.

Can MC74AC14NG drive an LED directly?

Yes, MC74AC14NG can drive a standard 2 mA LED directly via its output pin when configured in active-low mode (output low = LED on), leveraging its 24 mA sink capability. With V_CC = 5 V and a red LED (V_F ≈ 1.8 V), a 150 Ω series resistor yields ~21 mA - well within the rated I_OL limit. However, avoid sourcing current (output high) for LED anode drive due to lower IOH spec (−24 mA) and potential voltage droop. Always confirm thermal dissipation in high-duty-cycle scenarios, as sustained 24 mA per channel affects junction temperature. This capability applies specifically to MC74AC14NG, not generic logic inverters.

Is MC74AC14NG pin-compatible with MC74ACT14?

Yes, MC74AC14NG is pin-compatible with MC74ACT14 - both share identical SOIC-14 and TSSOP-14 footprints and 14-pin functional mapping (six inverters, GND, V_CC). However, they differ electrically: MC74ACT14 accepts TTL inputs (VIH = 2.0 V), while MC74AC14NG requires CMOS-level inputs (VIH ≈ 3.2 V at 4.5 V). Swapping them without verifying source logic levels may cause functional failure. Therefore, MC74AC14NG is not a drop-in replacement for MC74ACT14 in TTL-driven systems - always validate input compatibility before substitution in existing designs using MC74AC14NG.