STMicroelectronics L78L10ACUTR

Overview

L78L10ACUTR from STMicroelectronics is a three-terminal positive linear voltage regulator delivering a fixed 10 V output at up to 100 mA, featuring ±4% output voltage tolerance (A grade), thermal overload protection, and short-circuit protection. It requires no external components and is used for local on-card regulation in industrial control modules, sensor signal conditioning circuits, and low-power microcontroller power rails.

For engineers reviewing the L78L10ACUTR datasheet, L78L10ACUTR pinout, L78L10ACUTR application, or L78L10ACUTR equivalent, this device serves as a drop-in replacement for legacy 78Lxx regulators where tight output accuracy, low quiescent current (6 mA typ.), and robust fault protection are required in space-constrained designs.

Technical Context

The L78L10ACUTR employs internal current limiting and thermal shutdown circuitry, enabling operation without external protection components. Its architecture integrates bandgap reference, error amplifier, and pass transistor in a monolithic structure optimized for stability with minimal input/output capacitance (0.33 µF/0.1 µF).

It operates across an input voltage range of 12.5 V to 23 V for reliable 10 V regulation, maintains load regulation of ≤40 mV (1–40 mA), and achieves supply voltage rejection of 37–45 dB at 120 Hz - critical for noise-sensitive analog front-ends and mixed-signal systems.

Key Specifications

Pinout & Package

Supplied in SOT-89 package: compact surface-mount outline with exposed die attach pad for enhanced thermal performance (R_thJA = 55 °C/W with 6 cm² copper pour). Pin 1 = Input, Pin 2 = Ground, Pin 3 = Output.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM78L10ACZ and MC78L10ACDR2G, the L78L10ACUTR offers tighter tolerance (±4%), lower noise (60 µV vs. 100 µV), and superior thermal resistance (55 °C/W vs. 200 °C/W), making it optimal for high-density, noise-critical industrial control designs.

Availability

L78L10ACUTR is available at Aetrix Electronics and suitable for industrial sensor interfaces, embedded microcontroller power rails, and programmable logic controller modules requiring stable component supply and long-term production continuity.

Supply support for L78L10ACUTR 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 sensing 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 applications requiring robustness, simplicity, and guaranteed performance across extended temperature ranges (0 to 125 °C).

FAQ

What is the minimum input voltage required for stable 10 V output?

The L78L10ACUTR requires a minimum input voltage of 12.5 V to maintain regulation across its full 100 mA load range and operating temperature (0–125 °C), based on its 1.7 V typical dropout voltage. At light loads (<10 mA), regulation holds down to ~11.7 V, but design margin should preserve ≥12.5 V under worst-case conditions.

Can this regulator be used with ceramic output capacitors?

Yes - the L78L10ACUTR is explicitly characterized and stable with 0.1 µF ceramic output capacitors, as confirmed in ST's DS0424 Rev 30 test conditions. No ESR requirements apply, enabling use of low-ESR X7R or C0G types without risk of oscillation.

Does the SOT-89 package require PCB copper pour for thermal performance?

Yes - the SOT-89 package's thermal resistance (R_thJA = 55 °C/W) assumes 6 cm² of 2-oz copper connected to Pin 2 (ground) and the exposed thermal pad. Without this, R_thJA degrades to >100 °C/W, risking thermal shutdown above ~60 mA continuous load.

How does the ±4% tolerance affect system-level accuracy?

The ±4% output tolerance (9.6–10.4 V) directly impacts downstream analog circuits: for a 10-bit ADC with 10 V reference, it introduces up to ±16 LSB offset error. System calibration or ratiometric design mitigates this, but the tighter A-grade tolerance reduces need for trimming versus ±8% C-grade variants.