STMicroelectronics L78L08ACZTR

Overview

L78L08ACZTR from STMicroelectronics is a fixed-output +8 V, 100 mA positive linear voltage regulator in TO-92 package, featuring thermal overload and short-circuit protection, ±4% output voltage tolerance at 25 °C, 1.7 V dropout voltage, and 60 µV RMS output noise (10 Hz–100 kHz). It delivers stable local regulation for microcontroller I/O rails, sensor biasing, and low-power analog circuitry.

For engineers reviewing the L78L08ACZTR datasheet, L78L08ACZTR pinout, L78L08ACZTR application, or L78L08ACZTR equivalent, this page provides verified electrical specs, thermal performance data, TO-92 terminal mapping, real-world use cases, and validated alternative parts for industrial control, automotive body electronics, and embedded power management design.

Technical Context

The L78L08ACZTR implements a monolithic three-terminal linear regulator architecture with internal current limiting, thermal shutdown, and no external compensation required. Its output is stabilized across input voltages from 10.5 V to 23 V and load currents up to 100 mA, with line regulation of ≤125 mV and load regulation of ≤40 mV over temperature.

Designed for simplicity and robustness, it replaces Zener-diode/resistor regulators with lower quiescent current (6 mA typ. at 25 °C), improved ripple rejection (37–45 dB at 120 Hz), and tighter output accuracy-enabling reliable operation in space-constrained PCB layouts without heatsinking under moderate ambient conditions.

Key Specifications

Pinout & Package

TO-92 package: 3-pin through-hole plastic case with standard lead spacing (E = 3.30–3.94 mm, D = 4.45–4.95 mm), RoHS-compliant, ECOPACK2 certified.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM78L08ACZ/NOPB and MC78L08ACP, the L78L08ACZTR offers superior output accuracy (±4% vs. ±5%), lower noise (60 µV vs. ≥80 µV), and guaranteed operation up to +125 °C junction - making it optimal for safety-critical or high-reliability embedded systems.

Availability

L78L08ACZTR is available at Aetrix Electronics and suitable for industrial automation, automotive body electronics, and medical sensor systems requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for L78L08ACZTR 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 silicon solutions for automotive, industrial, and smart power applications.

The L78L series belongs to ST's legacy linear regulator product line, engineered specifically for cost-effective, robust local regulation in space- and reliability-constrained embedded systems - emphasizing simplicity, protection, and wide-temperature operation.

FAQ

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

The L78L08ACZTR requires a minimum input voltage of 9.7 V to maintain regulation at full 100 mA load, based on its 1.7 V dropout specification. At lighter loads (e.g., 40 mA), input can be as low as 9.5 V. Operation below dropout causes output to track input minus dropout, compromising regulation.

Can this regulator be used in parallel to increase output current?

No - the L78L08ACZTR lacks built-in current-sharing capability and has no output current balancing features. Paralleling units risks thermal runaway due to mismatched dropout voltages and quiescent currents. For >100 mA, use an external pass transistor or select a higher-current regulator like L7808CD2T.

Is a heat sink required for continuous 100 mA operation?

In still air with standard TO-92 mounting on 1 oz copper, no external heat sink is required for 100 mA at ambient ≤50 °C. Thermal resistance junction-to-ambient is 200 °C/W; power dissipation at 100 mA and 5 V drop is 500 mW, resulting in ~100 °C rise - within the 125 °C max junction limit. Above 50 °C ambient, board-level copper area is recommended.

Does this part support reverse-polarity input protection?

No - the L78L08ACZTR has no internal reverse-voltage protection. Applying negative input relative to GND may damage the IC. External protection (e.g., series diode or MOSFET-based ideal diode) must be added if reverse polarity exposure is possible in the system environment.