onsemi MC79L05ACHX

Overview

MC79L05ACHX from ON Semiconductor is a fixed-output, three-terminal negative linear voltage regulator delivering −5.0 V at up to 100 mA, featuring internal thermal overload protection and short-circuit current limiting in a SOT-89 package. It operates across 0°C to +125°C and requires no external components for basic regulation in low-power analog or digital supply rails.

For engineers reviewing the MC79L05ACHX datasheet, pinout, applications, or equivalent options, key selection factors include its −5 V output tolerance (±5%), dropout voltage of 1.7 V at +25°C, ripple rejection of 41–60 dB at 120 Hz, input voltage range (−7 V to −20 V), and quiescent current (2.0–5.5 mA).

Technical Context

This device implements a monolithic bipolar linear regulator architecture with built-in current limiting and thermal shutdown circuitry. Its output voltage is stabilized using an internal bandgap reference and error amplifier driving a pass transistor, enabling stable operation without external compensation under typical load conditions.

It is designed for use in dual-rail systems alongside complementary positive regulators like MC78L05A, requiring a common ground and minimum input-to-output differential of 2.0 V even under ripple conditions. Input bypassing with ≥0.33 μF and output bypassing with ≥0.1 μF are recommended for stability and transient response.

Key Specifications

Pinout & Package

SOT-89 (JEDEC TO-243, Option AA) - surface-mount, thermally enhanced 3-lead plastic package with exposed tab for improved heat dissipation; lead pitch 1.5 mm, body size 4.5 × 2.5 × 1.5 mm.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar negative voltage regulator applications.

Compared with LM79L05ACZ and MC79L05ACP, the MC79L05ACHX offers superior thermal performance in SMT layouts, enables automated assembly, and supports higher ambient operating temperatures due to its lower θ_JA, making it preferred for modern compact industrial and automotive control modules.

Availability

MC79L05ACHX is available at Aetrix Electronics and suitable for industrial sensor nodes, RS-232 interface modules, and low-power microcontroller peripherals requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MC79L05ACHX 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

ON Semiconductor is a global semiconductor manufacturer specializing in energy-efficient power management, analog, sensing, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The MC79L05ACHX belongs to ON Semiconductor's legacy linear regulator product line, originally developed by Fairchild and optimized for reliable, low-cost negative voltage generation in resource-constrained embedded systems.

FAQ

What is the maximum input voltage rating for MC79L05ACHX?

The absolute maximum input voltage for MC79L05ACHX is −30 V. However, the recommended operating input range is −7 V to −20 V per the electrical characteristics table. Exceeding −20 V may degrade line regulation and increase power dissipation beyond safe limits, especially at elevated temperatures.

Does MC79L05ACHX require input and output capacitors?

MC79L05ACHX does not require external capacitors for basic regulation, but input bypassing with ≥0.33 μF and output bypassing with ≥0.1 μF are strongly recommended. These capacitors improve stability, reduce high-frequency noise, and enhance transient response-especially when the regulator is located remotely from the main filter capacitor.

What is the thermal shutdown threshold of MC79L05ACHX?

The MC79L05ACHX incorporates internal thermal overload protection that activates when the junction temperature exceeds approximately +165°C. The device latches off until the die cools below the hysteresis threshold (~140°C), then resumes normal operation. This protects against sustained overloads and poor heatsinking scenarios.

Can MC79L05ACHX be used in place of LM79L05ACZ?

MC79L05ACHX and LM79L05ACZ share identical electrical specifications including −5 V output, 100 mA current capability, and thermal/short-circuit protection. However, they differ in package (SOT-89 vs. TO-92) and thermal performance-MC79L05ACHX has lower thermal resistance and is surface-mount only.

Is MC79L05ACHX suitable for automotive applications?

MC79L05ACHX is specified for 0°C to +125°C operation and meets industrial reliability standards, but it is not AEC-Q100 qualified. For automotive applications requiring qualification, ON Semiconductor offers AEC-Q100-compliant alternatives such as NCV79L05ABDTRKG, which shares the same −5 V output and 100 mA rating but includes extended temperature and qualification validation.