Send an Inquiry

To receive a quote for your project, please fill in the following information, and we’ll get back to you promptly.

Submit Inventory List

Please fill in the following information, and we’ll get back to you promptly.

Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Voltage Regulators - Linear, Low Drop Out (LDO) Regulators

STMicroelectronics L78S05CV-DG

Name: L78S05CV-DG
Brand: STMicroelectronics
SKU: L78S05CV-DG
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: L78S05CV-DG

Manufacturer:: STMicroelectronics

Category:: Voltage Regulators - Linear, Low Drop Out (LDO) Regulators

Package:: TO-220-3

Datasheet:: L78S05CV-DG.pdf

Description:: IC REG LINEAR 5V 2A TO220

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:4,813

Please send an inquiry. Send us your inquiry, and we will respond immediately.

Product details

Overview

L78S05CV-DG from STMicroelectronics is a fixed-output +5 V, 2 A positive linear voltage regulator in TO-220 package, featuring internal current limiting, thermal shutdown, and safe operating area (SOA) protection. It delivers stable local regulation for power rails in industrial control modules, motor drive logic supplies, and embedded system auxiliary power domains with input voltage up to 35 V.

For engineers reviewing the L78S05CV-DG datasheet, L78S05CV-DG pinout, L78S05CV-DG application, or L78S05CV-DG equivalent, key selection criteria include dropout behavior at 2 A load, thermal resistance (5 °C/W junction-to-case), output noise (40 µV RMS), and short-circuit peak current capability (3 A).

Technical Context

The L78S05CV-DG implements a monolithic series pass transistor architecture with built-in foldback current limiting and thermal foldback. Its SOA protection prevents destruction during sustained overload or high differential voltage conditions, enabling robust operation without external current-sense circuitry.

It operates as a three-terminal fixed regulator requiring no external components for basic functionality, but supports adjustable output configurations via external resistors or transistors per Figures 19–21 of the datasheet. Input-to-output differential voltage range spans 2 V (minimum dropout at light load) to 30 V (max rated input for 5 V output).

Key Specifications

Parameter	Value and Actual Design Meaning
Output Voltage	5.0 V ±2% (4.8–5.2 V at 500 mA, 4.75–5.25 V at 1 A); ensures compatibility with 5 V TTL/CMOS logic and microcontroller I/O rails.
Max Output Current	2 A continuous; enables direct powering of multiple ICs or small motors without external pass devices.
Differential Input Range	Min 2 V dropout (typical at low load); max 35 V DC input (absolute rating); supports wide-input unregulated supplies.
Thermal Resistance	5 °C/W junction-to-case; mandates use of heatsink for >1 A operation in ambient >50 °C environments.
Output Noise	40 µV RMS (10 Hz–100 kHz); suitable for analog sensor signal chains and low-noise MCU reference supplies.
Supply Rejection	54 dB at 120 Hz; suppresses ripple from rectified AC inputs, reducing need for large bulk capacitance.
Short-Circuit Peak	3 A (guaranteed by design); withstands brief fault events without latch-up or permanent damage.

Pinout & Package

Supplied in TO-220 (dual gauge) package with vertical mounting orientation, metal tab electrically connected to Pin 2 (Ground). Requires mechanical isolation when heatsinked to chassis ground.

Pin/Terminal	Circuit Role	Design Meaning
Pin 1 (Input)	Unregulated DC input supply	Accepts 7–35 V DC; must be decoupled with ≥0.33 µF ceramic capacitor within 5 cm of pin.
Pin 2 (Ground)	Common reference node	Electrically tied to metal tab; serves as return path for load and quiescent current; critical for thermal conduction.
Pin 3 (Output)	Regulated +5 V output	Delivers up to 2 A; requires ≥0.1 µF ceramic capacitor at output for transient stability per Figure 17.

Key Features

Feature	Design Value
Integrated SOA Protection	Prevents second breakdown of series pass transistor under high V_IN–V_OUT and high-current stress, eliminating need for external foldback circuitry.
Thermal Shutdown Threshold	Activates at ~150 °C junction temperature and holds until T_J drops to ~135 °C, enabling automatic recovery after overheating.
Low Quiescent Current	8 mA typical (independent of load); minimizes standby power loss in always-on subsystems.
Output Resistance	17 mΩ at 1 kHz; ensures <100 mV load regulation shift from 20 mA to 2 A, critical for stable digital rail performance.
Input Short-Circuit Immunity	Protected against input collapse with high-output capacitance loads via external diode recommendation (Figure 37), preventing BE-junction reverse breakdown.

Applications

Industrial PLC I/O Module Power

Motor Drive Logic Supply

Use Scenario: Powers isolated 5 V logic rails for digital input/output cards in programmable logic controllers handling 24 V field signals.

IC Role / Device Role / Timing Role: Local point-of-load regulator converting 24 V backplane supply to clean 5 V for optocoupler drivers and FPGA configuration interfaces.

Use Value: Internal SOA and thermal protection eliminate need for external current limiting, reducing BOM count and board space in dense I/O modules.

Use Scenario: Supplies gate drivers and microcontroller cores in 3-phase inverter boards where EMI and thermal cycling are severe.

IC Role / Device Role / Timing Role: Primary 5 V auxiliary rail generator downstream of bulk DC-DC converter, supporting real-time PWM timing and fault monitoring circuits.

Use Value: 54 dB ripple rejection at 120 Hz suppresses switching noise from upstream converters, ensuring jitter-free timer operation.

Embedded System Auxiliary Rail

Test Equipment Power Subsystem

Use Scenario: Generates stable 5 V for USB host controllers, Ethernet PHYs, and SD card interfaces in networked edge devices.

IC Role / Device Role / Timing Role: Secondary regulated rail decoupled from main 3.3 V domain, isolating noise-sensitive communication peripherals.

Use Value: 40 µV RMS output noise meets USB 2.0 eye diagram margin requirements without additional LDO post-regulation.

Use Scenario: Provides calibrated 5 V bias for precision DACs, ADC references, and op-amp signal conditioning stages in benchtop analyzers.

IC Role / Device Role / Timing Role: Low-drift, low-noise analog supply rail referenced to system ground, independent of digital supply fluctuations.

Use Value: -1.1 mV/°C output drift over 0–70 °C ensures <±0.1% voltage error across lab temperature ranges without calibration.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
LM7805CD2T	Lower max current (1.5 A), higher dropout (2 V min), R_thJA = 50 °C/W (vs. 50 °C/W for L78S05CV-DG), no SOA protection	Suitable only for ≤1 A loads with ample heatsinking; less robust under overload	Select when cost sensitivity outweighs current headroom and ruggedness requirements
MC7805BD2TR4	Same 1.5 A rating, tighter initial tolerance (±2% vs. ±2%), but lacks SOA protection and has higher output impedance (22 mΩ)	Acceptable for non-critical consumer-grade 5 V rails; not recommended for industrial overload-prone environments	Choose for legacy designs requiring pin-for-pin replacement with ON Semiconductor footprint

Compared with LM7805CD2T and MC7805BD2TR4, the L78S05CV-DG provides 33% higher current capacity, integrated SOA protection for fault resilience, and lower output impedance-making it preferable for industrial motor controls and PLCs where reliability under transient overload is mandatory.

Availability

L78S05CV-DG is available at Aetrix Electronics and suitable for industrial automation, motor control systems, and embedded test equipment requiring stable component supply with full production lifecycle support.

Supply support for L78S05CV-DG 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, specializing in power management, microcontrollers, and automotive ICs with strong industrial and embedded market focus.

The L78S series belongs to ST's legacy linear regulator product line, designed specifically for ruggedized industrial power conversion where simplicity, fault tolerance, and thermal resilience are prioritized over ultra-low quiescent current or switching efficiency.

FAQ

What is the minimum input voltage required for regulation at full 2 A load?

The L78S05CV-DG requires a minimum input voltage of 7 V to maintain 5 V output at 2 A load, per Table 4 (VI = 7 V, IO = 1 A condition extended to 2 A with derated dropout). Below this, output voltage collapses due to insufficient headroom across the series pass element.

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

No-L78S05CV-DG is not designed for parallel operation. Its output voltage tolerance (±2%) and lack of current-sharing features cause unequal load distribution, risking thermal runaway. For >2 A, use a single higher-current regulator or switch-mode solution.

Is an input capacitor mandatory, and what value is recommended?

Yes-an input capacitor is mandatory for stability. ST recommends ≥0.33 µF ceramic placed within 5 cm of Pin 1. Larger values (e.g., 10–100 µF aluminum electrolytic) improve ripple rejection but do not replace the ceramic for high-frequency decoupling.

Does the metal tab connect to any internal node, and how should it be mounted?

Yes-the metal tab is internally connected to Pin 2 (Ground). When mounted to a heatsink, electrical isolation (e.g., mica washer + thermal paste) is required unless the heatsink is grounded to the same reference. Mechanical mounting torque must not exceed 0.5 N·m to avoid package damage.

L78S05CV-DG Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: TO-220-3

Packaging:: Tube

Product Status:: Obsolete

Output Configuration:: Positive

Output Type:: Fixed

Number of Regulators:: 1

Voltage - Input (Max):: 35V

Voltage - Output (Min/Fixed):: 5V

Voltage - Output (Max):: -

Voltage Dropout (Max):: -

Current - Output:: 2A

Current - Quiescent (Iq):: 8 mA

Current - Supply (Max):: -

PSRR:: 54dB (120Hz)

Control Features:: -

Protection Features:: Over Current, Over Temperature, Short Circuit

Operating Temperature:: 0°C ~ 150°C

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-220

L78S05CV-DG FAQ

1.How can I place an order for L78S05CV-DG through Aetrix?

Please submit a Request for Quotation (RFQ) for L78S05CV-DG on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for L78S05CV-DG reliable?

The price and inventory of L78S05CV-DG are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L78S05CV-DG is usually 5 days.

3.What payment methods are accepted for L78S05CV-DG?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L78S05CV-DG transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for L78S05CV-DG?

L78S05CV-DG orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your L78S05CV-DG order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for L78S05CV-DG?

For technical support, including L78S05CV-DG datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L78S05CV-DG requirements.

6.How does Aetrix verify that L78S05CV-DG is sourced from the original manufacturer or authorized distributors?

All L78S05CV-DG products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that L78S05CV-DG meets industry standards.

7.What is the process for return or replacement of L78S05CV-DG?

All L78S05CV-DG units undergo pre-shipment inspection (PSI). If there is an issue with L78S05CV-DG, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The L78S05CV-DG part is unused and in its original packaging.

Return procedure for L78S05CV-DG:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

Tech Hub

2026-09-11 Comparator Circuit: Voltage Thresholds, Op-Amp Differences, LM393 and Practical Design

Comparator circuit design covering voltage thresholds, input limits, open-collector outputs, LM393 wiring, op-amp differences, hysteresis, timing, window detection and practical fault diagnosis.

2026-09-10 Schmitt Trigger Explained: Hysteresis, Circuits, Inverters and Applications

Schmitt triggers use separate rising and falling thresholds to stabilize slow or noisy signals. This guide covers hysteresis, 74HC14 and 74HCT14 selection, comparator calculations, RC oscillators and p…

2026-09-09 Counterfeit Electronic Components: How to Detect, Authenticate, and Test Suspect Parts

Counterfeit components can hide behind convincing markings and passing basic function tests. This engineering reference covers source traceability, external inspection, X-ray, XRF, electrical testing, …

2026-09-08 Obsolete Electronic Components: How to Source and Evaluate Replacements

A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.

2026-09-07 TTL vs CMOS Logic Levels: 74HC and 74HCT Compatibility Explained

TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.

2026-09-04 Logic Level Shifter: How to Connect 3.3V and 5V Logic Safely

A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.

2026-09-03 74HC595 vs TPIC6B595: Output Drive, Pinout, Current, and Load Selection

The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…

2026-09-02 74HC595 Pinout, Timing, Output Current, and Applications

The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…

2026-09-01 Latch vs Flip-Flop: Timing, Differences and Design Choices

A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…

2026-08-30 D Latch Circuit: Truth Table, Timing, ICs and Applications

A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …