onsemi MC74AC05MELG

Overview

MC74AC05MELG from onsemi is a hex inverter IC with open-drain outputs, designed for level-shifting and wired-OR logic applications in high-speed CMOS systems. It features 6 independent inverting buffers, TTL-compatible input thresholds (when used with pullups), ±24 mA output sink capability at VCC = 5.5 V, and operates across −40°C to +85°C. It is commonly deployed in I²C bus interface buffering and LED driver control stages.

For engineers reviewing the MC74AC05MELG datasheet, pinout, applications, or equivalent options, key selection criteria include open-drain drive strength, supply voltage range (2.0–6.0 V), input compatibility with both CMOS and TTL logic families, and SOIC-14 Pb-free packaging compliance.

Technical Context

The MC74AC05MELG implements six independent inverting gates using high-performance silicon-gate CMOS technology. Each output is open-drain, requiring external pull-up resistors to define HIGH-state voltage levels and enable wired-OR functionality. Input thresholds are CMOS-compatible (VIH = 2.1 V min at VCC = 3.0 V), and the device supports mixed-voltage interfacing when pullup resistors reference a different rail than VCC.

Propagation delay is specified at 6.0 ns max (tPLZ/tPZL) under 5.0 V/50 pF conditions, with guaranteed 24 mA sink current per output and low quiescent ICC ≤ 40 µA. The device exhibits no internal latch-up risk below 100 mA injection and meets JEDEC JESD78 Class II latch-up immunity.

Key Specifications

Pinout & Package

MC74AC05MELG is supplied in a 14-lead SOIC package (Case 751A), with 1.27 mm pitch, 8.75 mm × 3.90 mm body, and Pb-free (RoHS-compliant) finish. Pin 14 is VCC; Pin 7 is GND.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar hex inverter with open-drain applications.

Compared with SN74LVC05APWR and 74AHC05PW,118, MC74AC05MELG uniquely supports full 2.0–6.0 V operation with 24 mA sink at 5.5 V and 6.5 ns timing - making it the only option among the three qualified for robust 5 V industrial I²C extension and LED driving without voltage translation.

Availability

MC74AC05MELG is available at Aetrix Electronics and suitable for industrial automation interfaces, embedded sensor subsystems, and LED display controllers requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MC74AC05MELG 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 sensing solutions for automotive, industrial, and cloud infrastructure markets.

The MC74AC05MELG belongs to onsemi's 74AC logic family, engineered for high-speed, low-power CMOS operation in industrial and communications equipment where reliability, wide supply range, and open-drain flexibility are critical.

FAQ

What is the maximum sink current per output of the MC74AC05MELG?

The MC74AC05MELG guarantees 24 mA sink current per output at VCC = 5.5 V and TA = −40°C to +85°C, as specified in the Recommended Operating Conditions table. This rating applies under continuous DC conditions and supports direct driving of LEDs, small relays, and I²C bus loads without external amplification. Exceeding this limit risks parametric shift or thermal stress.

Does the MC74AC05MELG support 3.3 V logic systems?

Yes, the MC74AC05MELG operates reliably from 2.0 V to 6.0 V, including standard 3.3 V supplies. At VCC = 3.3 V, its VIH is guaranteed ≥1.7 V and VIL ≤1.0 V, ensuring compatibility with 3.3 V CMOS outputs. Its open-drain outputs also allow pullup to 5 V or other voltages - enabling true level shifting in mixed-voltage designs.

Is the MC74AC05MELG pin-compatible with TTL 74LS05?

Yes, the MC74AC05MELG is explicitly designed to be pinout-identical to the 74LS05, as stated in the datasheet: "The MC74AC/ACT05 is identical in pinout to the LS05." All six inverter inputs and outputs, plus VCC and GND, occupy matching positions in the SOIC-14 package - enabling drop-in replacement in legacy LS-based designs with improved speed and drive capability.

What is the purpose of the open-drain outputs in the MC74AC05MELG?

The open-drain outputs in the MC74AC05MELG allow multiple outputs to share a common pullup resistor and node - enabling wired-OR logic essential for I²C, SMBus, and interrupt bus architectures. Each output can only pull the line LOW; HIGH states rely on the external resistor, preventing bus contention and supporting multi-master arbitration without additional components.

Can the MC74AC05MELG be used without external pullup resistors?

No - the MC74AC05MELG cannot produce a valid HIGH output without external pullup resistors on its open-drain outputs. Since the internal output transistor lacks a pullup path, the output remains in high-impedance (floating) state when inactive. A pullup resistor to a defined voltage rail (e.g., 3.3 V or 5 V) is mandatory to establish the HIGH logic level and ensure proper signal termination.