onsemi MC78L15ACPRA

Overview

MC78L15ACPRA from onsemi is a 15 V, 100 mA fixed-output positive linear voltage regulator in TO-92 package with internal short-circuit current limiting and thermal overload protection. It delivers stable DC power for low-current analog circuits, sensor interfaces, and microcontroller peripherals requiring ±3% output accuracy and dropout voltage of 1.7 V at 25°C.

For engineers reviewing the MC78L15ACPRA datasheet, pinout, applications, or equivalent options, key selection criteria include input voltage range (17.5–30 V), load regulation (≤75 mV over 1–40 mA), ripple rejection (34–39 dB at 120 Hz), thermal resistance (200°C/W in TO-92), and automotive-grade NCV variants for AEC-Q100-compliant designs.

Technical Context

The MC78L15ACPRA uses a monolithic bipolar silicon design with built-in thermal shutdown and foldback current limiting. Its internal circuitry includes a precision bandgap reference, error amplifier, pass transistor, and protection logic - all integrated into a single die without external components required for basic operation.

It operates across an ambient temperature range of 0°C to +125°C and maintains regulation under line variations (17.5–30 V input) and load changes (1–40 mA). Dropout is defined as the minimum VI–VO differential (1.7 V typical) needed to sustain 2% output voltage deviation.

Key Specifications

Pinout & Package

MC78L15ACPRA is housed in a Pb-free TO-92 plastic package (Case 029), with leads bent for tape-and-reel delivery. The package has three terminals: Output (pin 1), Ground (pin 2), Input (pin 3).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC78L15ACPRA, NCV78L15ABPRAG adds automotive reliability assurance without altering electrical behavior, while MC78L15ACDR2G trades through-hole ease-of-use for superior thermal management and SMT scalability - both retain identical regulation specs and pin-compatible functionality within their respective packages.

Availability

MC78L15ACPRA is available at Aetrix Electronics and suitable for industrial sensor interfaces, legacy analog equipment upgrades, and microcontroller auxiliary rail generation requiring stable component supply, long-term lifecycle support, and RoHS-compliant through-hole packaging.

Supply support for MC78L15ACPRA 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-based solutions for automotive, industrial, cloud, and consumer markets.

The MC78L00A series was designed as a cost-effective, rugged fixed-voltage linear regulator family for low-current applications where simplicity, reliability, and thermal robustness outweigh efficiency concerns - targeting analog subsystems, legacy replacements, and space-constrained embedded controls.

FAQ

What is the maximum input voltage for MC78L15ACPRA?

The absolute maximum input voltage for MC78L15ACPRA is 40 Vdc for 24 V-rated versions, but per datasheet Electrical Characteristics, its specified operating input range is 17.5 Vdc to 30 Vdc for stable 15 V output regulation. Exceeding 30 Vdc risks violating line regulation specs and may trigger thermal shutdown under load. Always maintain ≥2 V headroom above output for reliable dropout margin.

Does MC78L15ACPRA require input and output capacitors?

MC78L15ACPRA does not require external capacitors for basic regulation, but a 0.33 µF input capacitor is recommended when lead length exceeds 5 cm from the power filter, and a 0.1 µF output capacitor improves transient response. These values are validated in Figure 2 of the datasheet and prevent oscillation or instability under dynamic load conditions.

What is the thermal resistance of MC78L15ACPRA in its TO-92 package?

MC78L15ACPRA in the TO-92 package (Case 029) has a thermal resistance of 200°C/W (Junction-to-Ambient) with no heatsink. This value assumes standard PCB mounting with minimal copper area; increasing copper pour around the GND pin lowers effective R_JA. At 25°C ambient, max continuous power dissipation is 625 mW before thermal shutdown activates.

Can MC78L15ACPRA be used as a current source?

Yes - MC78L15ACPRA can be configured as a constant-current source using the circuit in Figure 9 of the datasheet. By connecting the load between V_OUT and ground and adding a sense resistor from GND to a current-sink transistor base, output current is set by I_O ≈ 5.0 V / R. For example, a 50 Ω resistor yields ~100 mA, limited by the device's 100 mA absolute max rating and thermal constraints.

Is MC78L15ACPRA pin-compatible with other MC78LxxA variants?

Yes - all MC78LxxA devices (e.g., MC78L05ACPRA, MC78L12ACPRA) share identical TO-92 pinout: Pin 1 = V_OUT, Pin 2 = GND, Pin 3 = V_IN. This allows direct substitution across output voltages in existing layouts, provided input voltage headroom and load current requirements are met for the selected variant.