onsemi MC79L05ABDG

Overview

MC79L05ABDG from onsemi is a −5.0 V, 100 mA fixed negative voltage regulator in SOIC-8 package, featuring internal thermal shutdown and short-circuit current limiting. It delivers stable regulation for low-power analog circuits, sensor biasing, and dual-rail op-amp supplies where input voltage ranges from −7.0 V to −20 V.

For engineers reviewing the MC79L05ABDG datasheet, pinout, applications, or equivalent options, key selection criteria include dropout voltage (1.7 V at 40 mA), output voltage tolerance (±4%), ripple rejection (41–49 dB), and operation across −40 °C to +125 °C industrial temperature range.

Technical Context

The MC79L05ABDG implements a monolithic bipolar linear regulator architecture with built-in protection circuitry: thermal overload shutdown triggers at +150 °C junction temperature, and foldback current limiting activates under sustained overloads. Its internal reference and error amplifier maintain output regulation without external components in most applications.

Designed for fixed-output negative rail generation, it requires no external compensation capacitors under typical conditions but recommends 0.33 µF input and 0.1 µF output bypassing for stability with long trace lengths or large load capacitance. Input-to-ground and output-to-ground connections share a common ground reference.

Key Specifications

Pinout & Package

MC79L05ABDG uses an 8-pin SOIC-8 (Case 751) package with Pb-free finish. Pin 1 is Ground, Pins 2–3 are Input (Vin), Pin 4 is No Connect, Pin 5 is Ground, Pins 6–7 are Input (Vin), and Pin 8 is No Connect - per onsemi's official marking diagram and ordering information.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC79L05ACDG and LM79L05ACM/NOPB, the MC79L05ABDG uniquely combines extended temperature qualification, SOIC-8 surface-mount compatibility, and best-in-class 49 dB ripple rejection-making it optimal for high-reliability industrial PCBs where space, thermal performance, and environmental robustness are critical.

Availability

MC79L05ABDG is available at Aetrix Electronics and suitable for industrial sensor conditioning, dual-rail op-amp power supplies, and embedded peripheral interfaces requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MC79L05ABDG 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 focused on energy-efficient electronics, delivering silicon solutions for automotive, industrial, cloud, and IoT applications.

The MC79L00A Series was designed specifically for cost-sensitive, low-current negative voltage regulation in industrial control, instrumentation, and legacy system upgrades-emphasizing ruggedness, simplicity, and drop-in replaceability of discrete Zener solutions.

FAQ

What is the maximum input voltage rating for MC79L05ABDG?

The MC79L05ABDG has a maximum input voltage rating of −30 Vdc for the −5 V version. This limit applies at TA = +25 °C and ensures safe operation within absolute maximum ratings without device degradation. Exceeding −30 Vdc risks permanent damage even with thermal protection active.

Does MC79L05ABDG require external capacitors for stable operation?

MC79L05ABDG does not require external capacitors for basic regulation, but onsemi recommends a 0.33 µF input capacitor and 0.1 µF output capacitor for stability-especially with long input traces or large load capacitance. These values minimize high-frequency oscillation and improve transient response in real-world PCB layouts.

Is MC79L05ABDG pin-compatible with other regulators in the MC79L00A family?

Yes, all MC79L00A Series SOIC-8 variants-including MC79L05ABDG, MC79L12ABDG, and MC79L15ABDG-share identical pinouts and package dimensions. This allows board-level substitution across output voltages without layout changes, provided input voltage headroom and thermal design accommodate each variant's dropout and power dissipation.

What is the thermal resistance of MC79L05ABDG in SOIC-8 package?

The MC79L05ABDG in SOIC-8 (Case 751) has a junction-to-ambient thermal resistance (R_JA) of 180 °C/W at TA = +25 °C with minimum recommended copper pad size. Its junction-to-case resistance (R_JC) is 45 °C/W, enabling effective heat transfer to PCB copper when using appropriate thermal vias and ground plane area.

How does the internal current limiting function in MC79L05ABDG?

The MC79L05ABDG employs internal foldback current limiting that reduces output current during sustained short-circuit conditions-typically limiting peak current to ~150 mA while lowering voltage to protect the die. This behavior prevents thermal runaway and enables automatic recovery once the fault is removed, without requiring external current-sense circuitry.