onsemi MC79L12ACPRA

Overview

MC79L12ACPRA from ON Semiconductor is a three-terminal, fixed-output, negative-voltage linear regulator delivering −12 V at up to 100 mA. It features internal short-circuit current limiting, thermal overload protection, and requires no external components for basic operation. It is used in low-power analog circuits, sensor biasing, and dual-rail op-amp supplies where stable negative rail generation is required.

For engineers reviewing the MC79L12ACPRA datasheet, pinout, applications, or equivalent options, key selection criteria include guaranteed −12 V output tolerance (±4.2%), dropout voltage of 1.7 V at 40 mA, thermal shutdown behavior, TO-92 package thermal resistance (R_JA = 160°C/W), and compatibility with standard 0.33 µF input / 0.1 µF output capacitor configurations.

Technical Context

The MC79L12ACPRA implements a monolithic PNP pass transistor architecture with built-in bandgap reference, error amplifier, and protection circuitry. Its regulation loop maintains output stability across load currents from 1.0 mA to 100 mA and input voltages from −14.5 V to −27 V.

Thermal shutdown activates at +150°C junction temperature, and current limiting restricts peak output current under short-circuit conditions. The device operates over 0°C to +125°C ambient (AC grade) and exhibits 37–42 dB ripple rejection at 120 Hz with −15 V to −25 V input.

Key Specifications

Pinout & Package

MC79L12ACPRA is supplied in a Pb-free TO-92 package (Case 29), with leads bent for tape-and-reel automated assembly. The package has a thermal resistance of R_JA = 160°C/W and R_JC = 83°C/W, requiring minimal PCB copper area for low-power applications.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM7912ACZ and MC79M12CD2TG, the MC79L12ACPRA offers the lowest BOM count and smallest footprint for ≤100 mA loads, while maintaining superior noise performance and RoHS compliance - making it optimal for space-constrained, low-noise analog subsystems.

Availability

MC79L12ACPRA is available at Aetrix Electronics and suitable for industrial sensor conditioning, RS-232 interface power, and dual-rail op-amp supplies requiring stable component supply and long-term manufacturability.

Supply support for MC79L12ACPRA 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, and sensor solutions for automotive, industrial, and communications markets.

The MC79L00A Series was designed specifically for cost-sensitive, low-current negative voltage regulation in embedded control, instrumentation, and legacy interface applications - emphasizing ruggedness, simplicity, and long-lifecycle support.

FAQ

What is the maximum input voltage for MC79L12ACPRA?

The MC79L12ACPRA supports a maximum input voltage of −27 V under specified test conditions. Exceeding this value risks permanent damage, as the absolute maximum rating is −35 V for −12 V devices. Operation above −27 V reduces safety margin against transients and degrades thermal performance. Always maintain ≥2 V headroom between input and output to ensure regulation stability.

Does MC79L12ACPRA require input and output capacitors?

MC79L12ACPRA does not require external capacitors for basic regulation, but ON Semiconductor recommends a 0.33 µF input capacitor (tantalum or ceramic) and a 0.1 µF output capacitor for stability, especially with long input traces or large load capacitance. These values are validated in the datasheet's standard application circuit and prevent oscillation under transient load conditions.

What is the output voltage tolerance of MC79L12ACPRA over temperature?

The MC79L12ACPRA guarantees an output voltage of −12 V with ±4.2% tolerance (−11.4 V to −12.6 V) across its full operating temperature range of 0°C to +125°C. This specification is verified at 40 mA load and input voltages between −14.5 V and −27 V, and includes both initial accuracy and thermal drift contributions per the AC-grade characterization.

Can MC79L12ACPRA be used in automotive applications?

The MC79L12ACPRA is rated for 0°C to +125°C ambient operation (AC grade) and is not qualified to AEC-Q100 automotive standards. While it may function in non-safety-critical automotive environments, ON Semiconductor offers AB-grade variants (e.g., MC79L12ABPRAG) with −40°C to +125°C operation and extended testing for automotive use - MC79L12ACPRA itself is intended for industrial and commercial equipment only.

How does thermal shutdown behave in MC79L12ACPRA?

MC79L12ACPRA initiates thermal shutdown when junction temperature reaches +150°C, disabling the output until the die cools by ~15°C. Recovery is automatic and does not require power cycling. This behavior protects against sustained overload, inadequate heatsinking, or high ambient temperatures. The TO-92 package's R_JA = 160°C/W means >400 mW dissipation in still air will trigger shutdown - consistent with its 100 mA / 1.7 V dropout power limit.