STMicroelectronics L78L08ACD13TR

Overview

L78L08ACD13TR 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 over 0 to 125 °C junction temperature, and is specified for ±5% output voltage tolerance (AC grade). It serves as a robust local regulation solution in microcontroller power domains, sensor signal chains, and low-power industrial I/O modules.

For engineers reviewing the L78L08ACD13TR datasheet, L78L08ACD13TR pinout, L78L08ACD13TR application, or L78L08ACD13TR equivalent, key selection criteria include its 8 V ±5% output accuracy, 1.7 V dropout voltage, 37–45 dB supply voltage rejection at 120 Hz, 60 µV output noise (10 Hz–100 kHz), and SO-8 package with integrated thermal flag for PCB heat-sinking.

Technical Context

This device implements a monolithic series-pass regulator architecture with built-in foldback current limiting and thermal shutdown circuitry-enabling self-protecting operation without external supervision. Its SO-8 package integrates pins 2, 3, 6, and 7 electrically to the die attach flag, reducing thermal resistance (R_thJC = 20 °C/W max) when mounted on ≥6 cm² copper pour.

It functions as a drop-in replacement for Zener diode/resistor regulators, offering two orders of magnitude lower output impedance, reduced quiescent current (6 mA typ. at 25 °C), and improved line/load regulation (125 mV max line, 40 mV max load at 40 mA).

Key Specifications

Pinout & Package

Supplied in an SO-8 package with internal thermal enhancement: pins 2, 3, 6, and 7 are electrically connected to the die attach flag for low R_thJA (55 °C/W max with 6 cm² copper heat-sink).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM78L08ACM/NOPB and MC78L08ACP, the L78L08ACD13TR delivers lower output noise (60 µV vs. ≥80 µV), better thermal dissipation (55 °C/W vs. ≥120 °C/W), and tighter load regulation (40 mV vs. ≥60 mV), making it optimal for noise-sensitive, space-constrained, or high-reliability embedded power rails.

Availability

L78L08ACD13TR is available at Aetrix Electronics and suitable for industrial sensor nodes, microcontroller subsystems, IoT edge devices, and legacy equipment retrofits requiring stable component supply and long-term lifecycle support.

Supply support for L78L08ACD13TR 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 specializing in power management, microcontrollers, and analog ICs, with manufacturing aligned to ISO 9001 and AEC-Q200 standards.

The L78Lxx series was designed for cost-sensitive, reliability-critical local regulation in industrial, automotive, and consumer electronics-emphasizing robustness, minimal external components, and wide ambient operating range.

FAQ

What is the minimum input voltage required for stable 8 V output at 100 mA?

The L78L08ACD13TR requires a minimum input voltage of 9.7 V to maintain regulation at full 100 mA load, based on its 1.7 V dropout voltage specification. Input voltages below this threshold cause output collapse or unregulated behavior. For reliable operation across temperature and line variation, ST recommends ≥10.5 V nominal input.

Can this regulator be used with ceramic output capacitors?

Yes-the L78L08ACD13TR is stable with ceramic output capacitors as low as 0.1 µF, per ST's recommended test conditions. Unlike older 78Lxx variants, it does not require ESR-based damping, eliminating the need for tantalum or aluminum electrolytic capacitors and enabling compact, high-reliability layouts.

How does the SO-8 thermal flag improve power handling?

Pins 2, 3, 6, and 7 are internally bonded to the die attach flag, creating a low-thermal-resistance path from junction to PCB. With ≥6 cm² of 2-oz copper connected to these pins, R_thJA drops to 55 °C/W (vs. 200 °C/W in TO-92), allowing 100 mA continuous operation without external heatsinks under typical board conditions.

Is the L78L08ACD13TR RoHS and REACH compliant?

Yes-this part carries STMicroelectronics' ECOPACK®2 qualification, meeting RoHS Directive 2011/65/EU and REACH Regulation (EC) No. 1907/2006. The SO-8 package uses lead-free matte tin terminations and halogen-free molding compound, with full compliance documentation available via ST's quality portal.