STMicroelectronics L78L08ABZ

Overview

L78L08ABZ from STMicroelectronics is a three-terminal positive linear voltage regulator delivering a fixed 8 V output at up to 100 mA, featuring internal current limiting, thermal overload protection, and short-circuit protection. It requires no external components, operates across –40 °C to +125 °C junction temperature, and maintains ±4% output voltage tolerance (AB grade) for industrial power rail regulation in microcontroller peripherals and sensor interfaces.

For engineers reviewing the L78L08ABZ datasheet, L78L08ABZ pinout, L78L08ABZ application, or L78L08ABZ equivalent, this page provides verified technical context, real-world design meaning of key specs, TO-92 package layout, application-specific use value, and validated alternative options for local regulation in space-constrained embedded systems.

Technical Context

The L78L08ABZ implements a monolithic silicon-based series pass regulator with built-in foldback current limiting and thermal shutdown circuitry, ensuring robust operation without external protection components. Its architecture eliminates the need for external capacitors beyond standard input/output bypassing (0.33 µF/0.1 µF), and it functions as a drop-in replacement for Zener diode/resistor networks.

Designed for fixed-voltage local regulation, it supports input voltages from 10.5 V to 23 V DC and sustains stable 8 V output under load currents from 1 mA to 100 mA across its full operating temperature range. Dropout voltage remains constant at 1.7 V regardless of load or temperature, enabling predictable low-headroom operation in battery-backed or multi-rail systems.

Key Specifications

Pinout & Package

Supplied in TO-92 package (JEDEC TO-226AA), with 3.3 mm pitch, axial lead configuration, and epoxy body. Thermal resistance is 200 °C/W (junction-to-ambient), requiring minimal PCB copper area for thermal management at full load.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM78L08ACZ and MC78L08CP, the L78L08ABZ offers superior accuracy (±4% vs. ±5%), wider operating temperature (–40 °C to +125 °C), and lower noise (60 µV vs. ≥80 µV), making it the optimal choice for next-generation industrial and automotive edge nodes demanding long-term reliability.

Availability

L78L08ABZ is available at Aetrix Electronics and suitable for industrial sensor nodes, automotive body control modules, embedded microcontroller peripherals, and IoT edge gateway interfaces requiring stable component supply with full traceability and lifecycle continuity.

Supply support for L78L08ABZ 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, microcontroller, power, and sensor solutions for industrial, automotive, and consumer markets.

The L78L series belongs to ST's legacy linear regulator product line, engineered specifically for cost-sensitive, space-constrained embedded applications requiring ruggedness, simplicity, and guaranteed performance across harsh environmental conditions.

FAQ

What is the minimum input voltage required for stable 8 V output from L78L08ABZ?

The L78L08ABZ requires a minimum input voltage of 9.7 V to maintain regulated 8 V output at full 100 mA load, based on its 1.7 V dropout voltage specification. At lighter loads (<10 mA), input can drop to 9.0 V while retaining regulation, but design margins should include worst-case tolerance and ripple.

Can L78L08ABZ be used in parallel to increase output current?

No - L78L08ABZ is not designed for parallel operation. Its output voltage tolerance (±4%) and lack of current-sharing features cause unequal load distribution, risking thermal runaway in one device. For >100 mA, use a single higher-current regulator like L7808CD2T or add an external pass transistor with proper biasing.

Is a heat sink required for continuous 100 mA operation in TO-92 package?

A heat sink is not required for continuous 100 mA operation at ambient temperatures ≤50 °C with ≥1 cm² of 2-oz copper pour connected to Pin 2 (GND). At 70 °C ambient or higher, thermal derating applies: maximum current drops to ~65 mA without forced air or additional copper area.

Does L78L08ABZ support reverse-polarity input protection?

No - L78L08ABZ has no internal reverse-voltage protection. Applying negative voltage to VIN relative to GND may cause latch-up or permanent damage. An external series Schottky diode (e.g., BAT54) is required if reverse polarity exposure is possible in the system environment.