onsemi LM79L05ACZ

Overview

LM79L05ACZ from ON Semiconductor is a 3-terminal, fixed-output, negative-voltage linear regulator delivering −5.0 V at up to 100 mA, featuring internal thermal overload protection and short-circuit current limiting in a TO-92 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 LM79L05ACZ datasheet, pinout, applications, or equivalent options, this page provides verified specifications, TO-92 terminal mapping, real-world use cases in dual-rail power supplies, and two validated alternative parts with documented functional and packaging differences.

Technical Context

This device implements a monolithic PNP pass transistor topology with built-in current-limiting and thermal shutdown circuitry. Its −5 V output is trimmed to ±5% tolerance at 25°C and maintains stability over input voltages from −7 V to −20 V with load currents from 1.0 mA to 100 mA.

Line regulation is specified at 100 mV (−8 V ≤ VI ≤ −20 V), and load regulation is 30 mV (1.0 mA ≤ IO ≤ 40 mA). Dropout voltage is 1.7 V at 25°C, requiring minimum input of −6.7 V for regulated −5 V output under full load.

Key Specifications

Pinout & Package

LM79L05ACZ uses a 3-lead TO-92 plastic package with standard straight leads. The package is through-hole mountable, rated for 0.5 W dissipation at 25°C ambient, and compliant with JEDEC TO-92 outline.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC79L05ACP, LM79L05ACZ offers identical regulation performance and TO-92 compatibility but reflects Fairchild's original marking convention; versus LM79L05ACD, it avoids SMT reflow requirements and simplifies thermal design for low-volume or repair-focused deployments.

Availability

LM79L05ACZ is available at Aetrix Electronics and suitable for industrial sensor conditioning, dual-rail op-amp power supplies, and legacy control module repairs requiring stable component supply and long-term obsolescence support.

Supply support for LM79L05ACZ 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 supplier delivering energy-efficient, high-performance silicon solutions for automotive, industrial, cloud, medical, and edge applications.

The LM79L05ACZ belongs to ON Semiconductor's legacy linear regulator product line, designed specifically for cost-sensitive, low-current negative-voltage regulation in industrial and consumer electronics where simplicity, reliability, and TO-92 compatibility are critical.

FAQ

What is the maximum input voltage for LM79L05ACZ?

The absolute maximum input voltage for LM79L05ACZ is −30 V. However, the recommended operating range is −7 V to −20 V to ensure stable regulation and avoid excessive power dissipation. Exceeding −20 V increases dropout-related losses and thermal stress, especially above 100 mA load. Always verify input ripple amplitude stays within this window at the regulator's input pin.

Does LM79L05ACZ require input and output capacitors?

LM79L05ACZ does not require external capacitors for basic regulation, but input bypassing (≥0.33 μF) is recommended when wiring length exceeds 2 inches or when powering from noisy sources. An output capacitor (≥0.1 μF) improves transient response and stability. These values are specified in the datasheet for typical applications and must be placed with minimal lead length.

What is the thermal shutdown threshold of LM79L05ACZ?

LM79L05ACZ incorporates internal thermal shutdown that activates when the junction temperature exceeds approximately 160°C. Recovery occurs automatically once the die cools below the hysteresis threshold (~140°C). This protection is independent of ambient temperature and depends on power dissipation, PCB copper area, and airflow - no external thermal sensing is needed.

Can LM79L05ACZ be used in parallel to increase current capacity?

No, LM79L05ACZ is not designed for parallel operation. Its output voltage tolerance (±5%) and lack of current-sharing circuitry mean mismatched units will cause one device to dominate conduction, leading to thermal imbalance and potential failure. For >100 mA, select a higher-current regulator such as LM79M05 or use a discrete pass transistor stage.

Is LM79L05ACZ RoHS compliant and halogen-free?

Yes, LM79L05ACZ is RoHS compliant and halogen-free per ON Semiconductor's product change notification PCN-18001. The TO-92 package uses lead-free matte tin plating and meets JEDEC J-STD-020 moisture sensitivity level (MSL) 1. Full compliance documentation is available in the ON Semiconductor Quality & Reliability portal under part number LM79L05ACZ.