onsemi MC78L12ACPRE

Overview

MC78L12ACPRE from onsemi is a 100 mA, fixed +12 V positive linear voltage regulator in TO-92 package with internal short-circuit current limiting, thermal shutdown, and dropout voltage of 1.7 V at 25°C. It operates over 0°C to +125°C junction temperature and requires no external components for basic regulation in low-power industrial control, sensor interfaces, and legacy microcontroller supply rails.

For engineers reviewing the MC78L12ACPRE datasheet, pinout, applications, or equivalent options, this page delivers verified electrical specs, thermal behavior, real-world load/line regulation performance, and validated alternative options - all aligned with ON Semiconductor's Rev. 18 October 2016 datasheet.

Technical Context

The MC78L12ACPRE uses a monolithic bipolar silicon design with built-in thermal overload protection and internal current limiting. Its output voltage is trimmed to 11.5–12.5 V at 25°C under 40 mA load, with line regulation up to 250 mV across 14.5–27 V input range and load regulation up to 100 mV from 1–100 mA.

It exhibits 80 µV RMS output noise (10 Hz–100 kHz), 37–42 dB ripple rejection at 120 Hz, and maintains regulation down to a 1.7 V input-output differential - enabling use with modest unregulated supplies in space-constrained designs.

Key Specifications

Pinout & Package

MC78L12ACPRE is supplied in TO-92 package (Case 029), with leads formed straight and lead finish Pb-free. Thermal resistance is 200°C/W junction-to-ambient (no heatsink), requiring PCB copper area management for >150 mW dissipation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC78L12ACPREG, MC78L12ACPRE offers identical regulation performance but differs in packaging format and handling - making it ideal for engineering validation. Versus LM78L12ACZ, MC78L12ACPRE provides tighter output tolerance, lower bias current, and AEC-Q100 alignment for industrial reliability.

Availability

MC78L12ACPRE is available at Aetrix Electronics and suitable for industrial sensor interfaces, legacy microcontroller power, low-power analog front-ends, and point-of-load regulation requiring stable component supply and long-term manufacturability.

Supply support for MC78L12ACPRE 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 manufacturer specializing in energy-efficient power management, analog, and sensor solutions for automotive, industrial, and cloud infrastructure markets.

The MC78L00A series was designed to replace zener-diode-resistor regulators in cost-sensitive, low-current applications - delivering superior line/load regulation, thermal robustness, and simplified design without external components.

FAQ

What is the maximum input voltage for MC78L12ACPRE?

The absolute maximum input voltage for MC78L12ACPRE is 35 VDC for 12 V output variants, as specified in the Absolute Maximum Ratings table. Operation above this level risks permanent damage. For reliable regulation, input should remain within 14.5–27 V per electrical characteristics - ensuring dropout margin and thermal safety under full load and high ambient temperatures. Always verify input ripple amplitude does not cause instantaneous VI to exceed 35 V.

Does MC78L12ACPRE require input and output capacitors?

MC78L12ACPRE does not require capacitors for basic stability, but ON Semiconductor recommends a 0.33 µF input capacitor if the regulator is located >2 inches from the power supply filter, and a 0.1 µF output capacitor to improve transient response. These values are validated in Figure 2 of the datasheet and apply directly to MC78L12ACPRE under standard operating conditions.

What is the thermal resistance of MC78L12ACPRE in TO-92 package?

MC78L12ACPRE in TO-92 (Case 029) has a thermal resistance of 200°C/W junction-to-ambient with no heatsink, as stated in the Thermal Characteristics section. This value assumes standard PCB mounting with minimal copper; actual R_JA improves with added copper area. Power dissipation must be limited to avoid exceeding 150°C junction temperature - e.g., ≤150 mW at 50°C ambient.

Is MC78L12ACPRE RoHS compliant and lead-free?

Yes, MC78L12ACPRE is Pb-free and RoHS compliant, as confirmed in the Ordering Information and Package Dimensions sections. The "PRE" suffix denotes Pb-free TO-92 packaging with straight leads, and the device meets JESD97 and JEDEC Level 1 moisture sensitivity requirements. Marking includes "Pb-Free" notation per ON Semiconductor's compliance documentation.

How does MC78L12ACPRE compare to MC78L12ABPRE in terms of temperature range?

MC78L12ACPRE is rated for 0°C to +125°C junction temperature, while MC78L12ABPRE extends to −40°C to +125°C. The "C" suffix indicates commercial temperature grade; "B" denotes extended industrial/automotive grade. Both share identical electrical specs at 25°C, but MC78L12ABPRE guarantees performance across the full −40°C cold start range - critical for outdoor or automotive under-hood applications.