STMicroelectronics L78L05ABD13TR

Overview

L78L05ABD13TR from STMicroelectronics is a three-terminal positive linear voltage regulator delivering a fixed 5 V output at up to 100 mA, featuring internal current limiting, thermal overload protection, and short-circuit protection. It requires no external components for basic operation and is qualified for industrial temperature range (−40 °C to +125 °C), making it suitable for local on-card regulation in embedded power supplies and noise-sensitive analog subsystems.

For engineers reviewing the L78L05ABD13TR datasheet, L78L05ABD13TR pinout, L78L05ABD13TR application, or L78L05ABD13TR equivalent, key selection criteria include its ±4% output tolerance (AB grade), 2 V dropout voltage, 40 µV RMS output noise (10 Hz–100 kHz), 41–49 dB supply voltage rejection at 120 Hz, and SO-8 package with internally connected heat-sink pins (2, 3, 6, 7).

Technical Context

The L78L05ABD13TR implements a monolithic silicon-based series pass regulator architecture with built-in foldback current limiting and thermal shutdown circuitry. Its internal design eliminates the need for external compensation or stability components across all standard input/output conditions.

It operates as a fixed-output, single-supply linear regulator with a minimum input voltage of 7 V (for 5 V output) and maximum input of 30 V (VO = 5 V). The SO-8 package integrates the die attach flag electrically to pins 2, 3, 6, and 7-reducing thermal resistance to 20 °C/W junction-to-case and enabling higher sustained output current with PCB copper heat-sinking.

Key Specifications

Pinout & Package

Package: SO-8 (small outline integrated circuit, 8-pin), with internal thermal enhancement: pins 2, 3, 6, and 7 are electrically connected to the die attach flag to reduce thermal resistance (R_thJC = 20 °C/W max).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM78L05ACZ/NOPB and MC78L05ABDR2G, the L78L05ABD13TR offers superior thermal performance (R_thJC = 20 °C/W vs. >100 °C/W), tighter output tolerance (±4% vs. ±5%), and lower noise (40 µV vs. 55–65 µV), making it optimal for thermally demanding or precision analog applications.

Availability

L78L05ABD13TR is available at Aetrix Electronics and suitable for industrial sensor nodes, automotive body control modules, medical wearables, and smart home hub designs requiring stable component supply, long-term lifecycle support, and guaranteed traceability.

Supply support for L78L05ABD13TR 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 microcontrollers, power management ICs, sensors, and analog devices for industrial, automotive, and consumer markets.

The L78L series belongs to ST's legacy linear regulator product line, engineered specifically for robust, low-cost, no-frills fixed-voltage regulation in space-constrained and thermally challenging embedded systems.

FAQ

What is the minimum input voltage required for stable 5 V output?

The L78L05ABD13TR requires a minimum input voltage of 7 V to maintain regulation at full load (100 mA), based on its 2 V dropout voltage specification. At lighter loads (e.g., 10 mA), VI can be reduced to ~6.5 V while staying within regulation, but design margin should retain 7 V minimum to ensure stability across temperature and process variation.

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

No-L78L05ABD13TR is not designed for parallel operation. Its output voltage tolerance (±4%) and lack of current-sharing control circuitry would cause unequal current distribution and possible thermal runaway. For >100 mA, use a higher-current regulator (e.g., L7805CD2T) or add an external pass transistor per Figure 14 in DS0424.

Is a bypass capacitor required on the input pin?

Yes-a 0.33 µF ceramic capacitor is mandatory between pin 1 (or pin 8) and ground, placed as close as possible to the device. This prevents high-frequency oscillation and improves transient response. The datasheet specifies this for all operating conditions and is not optional for stable regulation.

Does the SO-8 package require special PCB layout for thermal performance?

Yes-the SO-8 package uses pins 2, 3, 6, and 7 as thermal vias to the die attach flag. To achieve the rated R_thJA = 55 °C/W, at least 6 cm² of 2-oz copper connected to these pins via ≥6 thermal vias (0.3 mm diameter) is required. Without this, junction temperature may exceed 125 °C at 100 mA.