onsemi MC78L05ABP

Overview

MC78L05ABP from onsemi is a 5.0 V, 100 mA fixed-output linear voltage regulator in TO-92 package, featuring internal short-circuit current limiting, thermal shutdown, and dropout voltage of 1.7 V at 25°C. It operates across −40°C to +125°C, requires no external components for basic regulation, and delivers stable output with 4.75–5.25 V tolerance under load (1–40 mA) and input (7–20 V).

For engineers reviewing the MC78L05ABP datasheet, pinout, applications, or equivalent options, this device serves as a cost-effective, rugged replacement for zener-resistor supplies in low-power embedded control, sensor interfaces, and automotive body electronics where wide temperature range and Pb-free compliance are required.

Technical Context

The MC78L05ABP uses a monolithic silicon design with PNP pass transistor and bandgap reference, enabling stable 5.0 V output without external compensation. Its thermal shutdown activates at ~150°C junction temperature, and internal current limit restricts output to ~150 mA during overload.

It exhibits 41–49 dB ripple rejection at 120 Hz and 40 µV RMS output noise (10 Hz–100 kHz), with line regulation ≤150 mV and load regulation ≤60 mV over specified conditions - confirming suitability for noise-sensitive analog subsystems and microcontroller power rails.

Key Specifications

Pinout & Package

MC78L05ABP uses TO-92 package (Case 029), with leads formed straight or bent per ordering variant (e.g., MC78L05ABPRMG = Ammo Pack, straight lead). Thermal performance relies on PCB copper area due to plastic package construction.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM78L05ACZ, MC78L05ABP offers wider temperature range and lower quiescent current for harsh environments; compared with NCV78L05ABPG, it lacks automotive qualification documentation but shares identical silicon and TO-92 mechanical form - making it ideal for industrial prototypes and non-OEM volume production.

Availability

MC78L05ABP is available at Aetrix Electronics and suitable for automotive body electronics, industrial sensor interfaces, consumer appliance control boards, and medical handheld diagnostics requiring stable component supply across extended temperature ranges.

Supply support for MC78L05ABP 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, with leadership in automotive, industrial, cloud, and sensing technologies.

The MC78L00A series was designed to replace zener-diode regulators in cost-sensitive, low-current applications - delivering improved line/load regulation, thermal robustness, and simplified bill-of-materials for legacy and new-design embedded systems.

FAQ

What is the maximum input voltage rating for MC78L05ABP?

The absolute maximum input voltage for MC78L05ABP is 30 V for 5.0–9.0 V output variants. This rating applies across the full −40°C to +125°C operating range and ensures safe operation during load dump or transient overvoltage events in automotive and industrial power systems. Exceeding 30 V risks permanent damage to the internal pass transistor and reference circuitry.

Does MC78L05ABP require input and output capacitors for stable operation?

MC78L05ABP does not require output capacitance for stability, but a 0.1 µF ceramic capacitor is recommended to improve transient response. An input bypass capacitor (≥0.33 µF tantalum or ceramic) is required if the regulator is located more than 10 cm from the power supply filter - otherwise, high-frequency instability or oscillation may occur under dynamic load conditions.

Can MC78L05ABP be used as a current source?

Yes, MC78L05ABP can be configured as a constant-current source by connecting a resistor between output and ground, with the load referenced to input. For example, a 50 Ω resistor yields ~100 mA output current (IO ≈ 5.0 V / R), limited by the device's 100 mA rating and thermal constraints. Dissipation must be calculated as (VI − 5 V) × IO to avoid exceeding 625 mW in TO-92.

How does thermal performance of MC78L05ABP compare across package types?

MC78L05ABP in TO-92 has R_JA = 200°C/W, limiting power dissipation to 625 mW at 25°C ambient. In contrast, SOIC-8 variants (e.g., MC78L05ABDG) achieve R_JA ≈ 120°C/W with 1-inch² copper, enabling ~1.0 W dissipation. SOT-89 versions offer R_JA = 55°C/W - making them preferable for higher-current or thermally constrained layouts where TO-92 cannot meet thermal targets.

Is MC78L05ABP pin-compatible with other 78L05 variants?

MC78L05ABP (TO-92) shares identical pinout (Output–Ground–Input) with all TO-92-packaged 78L05 devices including LM78L05ACZ and NCV78L05ABPG. However, SOIC-8 and SOT-89 variants have different pin counts and arrangements - so PCB layout changes are required when substituting across packages, even with identical electrical function.