onsemi MC79L12ABD

Overview

MC79L12ABD from ON Semiconductor is a 100 mA, −12 V fixed negative voltage regulator in SOIC-8 package with thermal shutdown and internal current limiting. It delivers stable regulation for low-power analog and digital subsystems requiring clean negative supply rails, such as op-amp biasing, sensor signal conditioning, and legacy RS-232 interface circuitry.

For engineers reviewing the MC79L12ABD datasheet, pinout, applications, or equivalent options, key selection criteria include its −12 V output accuracy (±4.2% over −40°C to +125°C), 1.7 V dropout at 40 mA, 37–42 dB ripple rejection at 120 Hz, and SOIC-8 thermal performance (R_JA = 180°C/W).

Technical Context

The MC79L12ABD implements a monolithic bipolar linear regulator architecture with built-in short-circuit current limiting and thermal overload protection. Its internal design eliminates need for external compensation components in most applications, supporting direct integration into space-constrained PCB layouts.

It operates across input voltages from −14.5 V to −27 V while maintaining regulated −12 V output under load currents up to 100 mA. The device features 80 µV_RMS output noise (10 Hz–100 kHz) and maintains regulation down to 1.7 V differential between input and output at 40 mA.

Key Specifications

Pinout & Package

MC79L12ABD uses the SOIC-8 (Case 751) package, 4.9 × 3.9 mm body, 1.27 mm lead pitch, with gull-wing leads and Pb-free finish. Thermal resistance is specified for minimum recommended copper pad size per Figure 9 of datasheet.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM7912CDT/NOPB and MC79L12ACDR2G, the MC79L12ABD uniquely combines wide-temperature operation (−40°C to +125°C), SOIC-8 compactness, and proven ruggedness in harsh industrial settings - making it optimal for embedded systems requiring field reliability without thermal derating penalties.

Availability

MC79L12ABD is available at Aetrix Electronics and suitable for industrial sensor interfaces, RS-232 transceivers, op-amp biasing, and microcontroller analog peripherals requiring stable component supply across extended temperature ranges.

Supply support for MC79L12ABD 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 (now onsemi) is a global semiconductor supplier specializing in energy-efficient power management, analog, sensing, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The MC79L12ABD belongs to the MC79L00A Series of three-terminal negative regulators, designed specifically for cost-sensitive, space-constrained applications needing reliable low-current negative voltage rails in industrial and legacy system upgrades.

FAQ

What is the guaranteed output voltage tolerance of the MC79L12ABD over temperature?

The MC79L12ABD guarantees an output voltage of −11.4 V to −12.6 V (±4.2%) across its full operating junction temperature range of −40°C to +125°C, as verified under load conditions of 1.0–40 mA and input voltages between −14.5 V and −27 V. This tolerance is tighter than standard 5% regulators and ensures compatibility with −12 V logic and analog standards.

Can the MC79L12ABD be used without input and output capacitors?

The MC79L12ABD can operate without external capacitors in low-noise, low-current applications with short input traces, but ON Semiconductor recommends a 0.33 µF input capacitor (tantalum or ceramic) and 0.1 µF output capacitor for stability, especially with long input wiring or large load capacitance. Omitting them risks oscillation or degraded transient response in real-world PCB layouts.

What is the maximum power dissipation of the MC79L12ABD in SOIC-8 package at +50°C ambient?

At +50°C ambient temperature, the MC79L12ABD in SOIC-8 package (R_JA = 180°C/W) has a maximum allowable power dissipation of approximately 555 mW, calculated using P_D(max) = (T_J(max) − T_A) / R_JA = (150 − 50) / 180 ≈ 0.555 W. This supports ~46 mA continuous output at −12 V with −20 V input, assuming no additional heatsinking.

Does the MC79L12ABD have built-in protection features?

Yes, the MC79L12ABD integrates two critical protection functions: internal short-circuit current limiting and thermal overload shutdown. These features activate automatically during output faults or excessive power dissipation, preventing permanent damage and enabling safe automatic recovery once fault conditions clear - eliminating need for external protection circuitry.

Is the MC79L12ABD pin-compatible with other devices in the MC79L00A Series?

Yes, all MC79L00A Series regulators-including MC79L05ABD, MC79L12ABD, MC79L15ABD, and MC79L24ABD-share identical SOIC-8 pinouts (Pins 1=V_OUT, 2–3–6–7=V_IN, 4–8=NC, 5=GND). This allows direct substitution across output voltages without PCB redesign, provided input voltage and load current remain within each variant's specified limits.