onsemi MC74AC14MELG

Overview

MC74AC14MELG 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 V_CC = 5.0 V), CMOS-compatible inputs and outputs, ±24 mA output drive capability, and operates across 2.0–6.0 V supply range. It is widely used in clock shaping, debouncing mechanical switches, and waveform regeneration in industrial control systems.

For engineers reviewing the MC74AC14MELG datasheet, pinout, applications, or equivalent options, this page delivers verified technical context, real-world design meaning of key specs, validated package and pin mapping, confirmed alternatives, and supply-chain support details specific to MC74AC14MELG - not generic AC-series logic.

Technical Context

The MC74AC14MELG implements six independent Schmitt-trigger input inverters using high-performance silicon-gate CMOS technology. Each inverter provides hysteresis between positive-going (V_t+) and negative-going (V_t−) thresholds - 3.2 V / 0.9 V typical at V_CC = 4.5 V - enabling robust noise rejection for slow-rising or noisy signals.

It delivers rail-to-rail CMOS output levels with guaranteed VOH ≥ 4.4 V and VOL ≤ 0.44 V at I_OH = −24 mA / I_OL = 24 mA and V_CC = 4.5 V, and supports propagation delays as low as 6.0 ns (t_PHL, typ.) under 5.0 V/50 pF conditions.

Key Specifications

Pinout & Package

MC74AC14MELG is packaged in a Pb-free SOIC-14 (Case 751A) surface-mount package measuring 8.75 mm × 3.90 mm × 1.75 mm, with 1.27 mm pitch and gull-wing leads.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LV14APWR and 74HC14D,653, MC74AC14MELG uniquely balances 6 V tolerance, 24 mA drive, and sub-12 ns propagation - making it optimal for industrial I/O conditioning where mixed-supply interoperability and robust signal integrity are essential.

Availability

MC74AC14MELG is available at Aetrix Electronics and suitable for industrial automation, embedded control, and instrumentation applications requiring stable component supply, long-term manufacturability, and consistent parametric performance across production lots.

Supply support for MC74AC14MELG 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, analog, sensing, and logic solutions for automotive, industrial, cloud, and IoT markets.

The MC74AC14MELG belongs to onsemi's high-speed AC-series logic family, engineered for noise-immune signal conditioning in harsh electrical environments - particularly targeting industrial control, motor drives, and sensor interface subsystems.

FAQ

What is the maximum supply voltage rating for MC74AC14MELG?

The absolute maximum DC supply voltage (V_CC) for MC74AC14MELG is +6.5 V, but the recommended operating range is 2.0 V to 6.0 V. Operation above 6.0 V risks exceeding internal oxide breakdown limits and may cause irreversible damage. For reliable long-term use in industrial designs, maintain V_CC ≤ 6.0 V with adequate decoupling, and always refer to the Absolute Maximum Ratings table in the official MC74AC14MELG datasheet for thermal and current derating guidance.

Does MC74AC14MELG support true TTL input compatibility?

No, MC74AC14MELG does not support TTL input compatibility - that feature applies only to the MC74ACT14 variant. MC74AC14MELG uses standard CMOS input thresholds (V_t+ ≈ 3.2 V, V_t− ≈ 0.9 V at V_CC = 4.5 V), which differ from TTL's 2.0 V/0.8 V thresholds. Attempting to interface MC74AC14MELG directly with 5 V TTL outputs may result in undefined logic states. For TTL-compatible operation, select MC74ACT14 or verify input voltage margins using the MC74AC14MELG's VIH/VIL specifications.

What is the typical hysteresis voltage of MC74AC14MELG at 5.0 V supply?

The typical hysteresis voltage (V_h = V_t+ − V_t−) for MC74AC14MELG is 1.4 V at V_CC = 4.5 V and 1.6 V at V_CC = 5.5 V; extrapolating linearly, it is approximately 1.5 V at 5.0 V. This value is internally set by transistor ratios and remains stable across temperature and supply variations - a key reason MC74AC14MELG is trusted for EMI-prone applications like motor control feedback and switch interfaces.

Can MC74AC14MELG drive an LED directly without a current-limiting resistor?

No, MC74AC14MELG must always be used with a series current-limiting resistor when driving an LED. Although its outputs can source/sink up to 24 mA, the absolute maximum output current per pin is 50 mA - and sustained operation near that limit degrades reliability. For a typical red LED (V_F ≈ 1.8 V) powered from 5 V, a minimum 130 Ω resistor is required to limit current to 24 mA. Omitting the resistor risks exceeding safe operating area (SOA) limits and premature device failure.

Is MC74AC14MELG pin-compatible with other hex Schmitt-trigger inverters in SOIC-14 packages?

Yes, MC74AC14MELG follows the industry-standard SOIC-14 pinout for hex inverters: pins 1–13 alternate input/output per gate, pin 7 is GND, and pin 14 is V_CC. This matches SN74LV14A, 74HC14, and CD74HC14 pin-for-pin. However, electrical differences - including drive strength, propagation delay, and input thresholds - mean functional substitution requires validation in the target circuit. Always verify timing margins, noise immunity, and loading behavior before drop-in replacement.