STMicroelectronics L78S10CV

Overview

L78S10CV from STMicroelectronics is a three-terminal fixed-output positive linear voltage regulator delivering 10 V at up to 2 A, featuring internal current limiting, thermal shutdown, and safe operating area (SOA) protection. It operates with input voltages up to 30 V (for ≤1 A load), exhibits 100 mV typical load regulation at 2 A, and is housed in a TO-220 package for industrial power supply local regulation.

For engineers reviewing the L78S10CV datasheet, L78S10CV pinout, L78S10CV application, or L78S10CV equivalent, key selection criteria include dropout behavior at 2 A, thermal resistance (5 °C/W junction-to-case), output noise (65 µV RMS, 10 Hz–100 kHz), and short-circuit peak current capability (3 A).

Technical Context

The L78S10CV implements a monolithic series pass transistor architecture with built-in foldback current limiting and thermal foldback, enabling robust operation under sustained overload or elevated ambient temperature. Its SOA protection prevents secondary breakdown during transient overloads, while the internal reference and error amplifier maintain ±5% output voltage accuracy across line, load, and temperature.

It requires no external compensation and remains stable without an output capacitor-though adding one improves transient response. Input-to-output differential voltage directly impacts power dissipation and thermal performance, with maximum junction temperature limited to 150 °C and R_thJC = 5 °C/W enabling >2 A delivery with adequate heatsinking.

Key Specifications

Pinout & Package

Supplied in TO-220 package (single-gauge variant, 3-pin vertical mount), with exposed metal tab electrically connected to Pin 2 (Ground) and thermally coupled to heatsink.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LM7810CT and MC7810CD2TR4, the L78S10CV uniquely combines 2 A continuous capability, integrated SOA protection, and thermal foldback-making it optimal for ruggedized 10 V supplies where overload resilience and thermal margin are prioritized over ultra-low noise or highest PSRR.

Availability

L78S10CV is available at Aetrix Electronics and suitable for industrial power supplies, automotive body electronics, test equipment power stages, and LED driver bias circuits requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for L78S10CV 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, designing and manufacturing microcontrollers, power management ICs, analog chips, and MEMS sensors for industrial, automotive, and consumer markets.

The L78S series belongs to ST's legacy linear regulator product line, engineered specifically for cost-effective, robust local regulation in harsh environments where reliability under overload, thermal stress, and voltage transients is mandatory.

FAQ

What is the minimum input voltage required for L78S10CV to regulate at full 2 A?

The minimum input voltage is determined by dropout: at 2 A, typical dropout is ~1.5 V (VI ≥ VO + 1.5 V = 11.5 V). However, electrical characteristics specify VI ≥ 12.5 V for guaranteed 10 V output at 500 mA, and ≥13 V for 1 A testing. For reliable 2 A operation across temperature and tolerance, VI ≥ 14 V is recommended to ensure margin against thermal derating and line sag.

Can L78S10CV be used without an output capacitor?

Yes-L78S10CV is internally compensated and stable without an output capacitor, per ST's datasheet (Section 6, Figure 17). However, a 0.33 µF ceramic capacitor at the output significantly improves load transient response, especially with fast-stepping loads like microcontrollers. No ESR requirements apply, unlike older 78xx variants.

How does thermal protection behave under sustained overload?

Under sustained overload, L78S10CV first activates current limiting (~500 mA short-circuit current), then thermal shutdown triggers at T_J ≥ 150 °C. After shutdown, the device cools passively and automatically recovers once T_J drops ~10 °C below trip point. This cycle repeats if overload persists-preventing destruction but limiting average output power without adequate heatsinking (R_thJA = 50 °C/W).

Is L78S10CV compatible with standard 7810 footprint layouts?

Yes-L78S10CV uses the industry-standard TO-220 package with identical pinout (Input-Ground-Output) and mechanical dimensions as LM7810CT and MC7810CD2TR4. The single-gauge variant matches common PCB footprints, and the tab (Pin 2) is Ground, enabling direct thermal mounting to heatsinks without insulating washers unless isolation is required.