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

STMicroelectronics L78S05CV

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

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Part No.:: L78S05CV

Manufacturer:: STMicroelectronics

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

Package:: TO-220-3

Datasheet:: L78S05CV.pdf

Description:: IC REG LINEAR 5V 2A TO220AB

Quantity:: RFQ Add To RFQ list

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Inventory:2,456

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Product details

Overview

L78S05CV from STMicroelectronics is a three-terminal positive linear voltage regulator IC delivering a fixed 5 V output with up to 2 A continuous current, thermal shutdown, short-circuit protection, and safe operating area (SOA) protection. It operates with input voltages up to 35 V (for 5 V output), features 50 mV typical load regulation at 2 A, and is housed in a TO-220 package for high-power dissipation in industrial power supplies and embedded control systems.

For engineers reviewing the L78S05CV datasheet, L78S05CV pinout, L78S05CV application, or L78S05CV equivalent, key selection criteria include dropout behavior under 2 A load, thermal resistance (5 °C/W junction-to-case), quiescent current stability (8 mA typ.), and compatibility with local on-card regulation in space-constrained PCB layouts.

Technical Context

The L78S05CV uses an internal NPN series pass transistor with integrated current limiting, thermal foldback, and SOA protection circuitry - enabling robust operation without external protection components. Its architecture supports fixed-output operation but allows adjustable configurations via external resistors or feedback networks.

It maintains regulation across input voltages from 7 V to 35 V and junction temperatures from 0 °C to 150 °C, with output voltage drift of −1.1 mV/°C over 0–70 °C. Ripple rejection is 54 dB at 120 Hz, and output impedance is 17 mΩ at 1 kHz, confirming low-noise, high-stiffness performance for analog-sensitive loads.

Key Specifications

Parameter	Value and Actual Design Meaning
Output voltage	5.0 V ±2% (4.8–5.2 V), stable under 2 A load and 7–25 V input
Max output current	2 A continuous, limited by internal SOA protection and thermal design
Input voltage range	7 V to 35 V DC - minimum 2 V headroom required for regulation at full load
Load regulation	80 mV max from 20 mA to 2 A - ensures stable rail for dynamic digital loads
Thermal resistance	5 °C/W junction-to-case - mandates heatsink for >1 A sustained operation
Quiescent current	8 mA typical - enables predictable standby power budgeting
Noise voltage	40 µV RMS (10 Hz–100 kHz) - suitable for analog sensor front-ends

Pinout & Package

Supplied in TO-220 package with vertical mounting orientation, metal tab electrically connected to Pin 2 (Ground), requiring insulated mounting hardware when chassis-grounded.

Pin/Terminal	Circuit Role	Design Meaning
Pin 1 (Input)	V_IN	Unregulated DC input; must be ≥7 V and ≤35 V for stable 5 V output
Pin 2 (Ground)	GND	Common reference for input and output; metal tab is internally tied to this pin
Pin 3 (Output)	V_OUT	Regulated +5 V output; requires ≥0.33 µF ceramic capacitor for transient stability

Key Features

Feature	Design Value
Internal SOA protection	Prevents destruction during overload or short-circuit events without external current-sense circuitry
Thermal shutdown	Activates at ~150 °C junction temperature and auto-recovers after cooldown
Short-circuit current limit	500 mA typical sustained, 3 A peak - protects downstream circuitry during fault conditions
Low output impedance	17 mΩ at 1 kHz - minimizes voltage sag during fast load transients (e.g., microcontroller wake-up)
No external capacitor required	Stable without output capacitor, though 0.33 µF improves transient response and EMI filtering

Applications

Industrial PLC Power Rails

Automotive Body Control Modules

Use Scenario: Local 5 V supply for I/O expansion cards in programmable logic controllers with ambient temperatures up to 70 °C.

IC Role / Device Role / Timing Role: Primary linear regulator providing clean, protected 5 V rail for microcontrollers, optocouplers, and relay drivers.

Use Value: Eliminates single-point regulation distribution losses and withstands motor-induced voltage spikes due to built-in short-circuit and thermal protection.

Use Scenario: On-board 5 V generation for body control units in 12 V automotive systems with cold-crank (6.5 V min) and load-dump (35 V max) tolerance.

IC Role / Device Role / Timing Role: Fixed-output voltage regulator handling wide-input transients while powering CAN transceivers and EEPROMs.

Use Value: Maintains regulation down to 7 V input and survives 35 V surges without latch-up, reducing need for upstream TVS clamping.

Medical Diagnostic Instrumentation

Point-of-Sale Terminal Logic Supply

Use Scenario: Low-noise 5 V source for ADC reference and signal conditioning stages in portable ultrasound front-ends.

IC Role / Device Role / Timing Role: Precision analog supply regulator with 40 µV RMS noise and <100 mV load regulation.

Use Value: Enables 12-bit+ effective resolution by minimizing power-supply-induced quantization error in sensitive analog paths.

Use Scenario: Compact 5 V rail for ARM-based payment terminals with space-limited PCBs and intermittent 2 A peak loads (thermal print head activation).

IC Role / Device Role / Timing Role: High-current local regulator replacing bulkier switching solutions where EMI sensitivity prohibits SMPS use.

Use Value: Delivers 2 A peak current with TO-220 footprint and no switching noise - critical for contactless card reader RF integrity.

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
LM7805CT	Lower max current (1.5 A), higher dropout (2 V min), 80 °C max junction temp	Suitable only for ≤1.2 A continuous loads; less robust under thermal stress	Select when cost is primary and thermal margin exceeds 25 °C
MC7805CD2TR4G	1.5 A rating, tighter initial accuracy (±2% vs ±2%), same TO-220 package	Lacks SOA protection - requires external current limiting for >1 A fault conditions	Choose for legacy designs where SOA is managed externally and ripple rejection >50 dB is not required

Compared with LM7805CT and MC7805CD2TR4G, the L78S05CV offers superior current capability (2 A vs 1.5 A), enhanced protection (integrated SOA vs none), and wider input range (35 V vs 30 V), making it preferred for high-reliability industrial and automotive applications demanding fault resilience without added protection circuitry.

Availability

L78S05CV is available at Aetrix Electronics and suitable for industrial PLC power rails, automotive body control modules, medical diagnostic instrumentation, and point-of-sale terminal logic supplies requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for L78S05CV 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 discrete devices for industrial, automotive, and consumer markets.

The L78S series belongs to ST's legacy linear regulator product line, engineered specifically for ruggedized fixed-voltage local regulation in harsh environments where reliability, thermal resilience, and fault tolerance outweigh efficiency concerns.

FAQ

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

The L78S05CV requires a minimum input voltage of 7 V to maintain 5 V output at 2 A load, per datasheet test conditions (VI = 7 V, IO = 1 A). At full 2 A, headroom increases slightly due to internal drop; 7.5 V is recommended for margin. Dropout voltage rises with junction temperature - see Figure 8 in the datasheet for derating curves.

Can L78S05CV be used in adjustable-output configurations?

Yes - the L78S05CV can be configured as an adjustable regulator using external resistors and feedback networks, as shown in Figures 19–21 of the datasheet. Its internal reference and error amplifier allow output voltages from 5 V up to 30 V, though stability and thermal limits must be re-evaluated for non-standard configurations.

Is a heat sink mandatory for 2 A continuous operation?

Yes - with R_thJC = 5 °C/W and R_thJA = 50 °C/W, dissipating ~10 W at 2 A (e.g., 12 V_IN → 5 V_OUT) raises junction temperature rapidly. Without a heatsink, case temperature exceeds safe limits within seconds. A 10 °C/W heatsink is recommended for continuous 2 A operation at ambient ≤50 °C.

Does L78S05CV require an input bypass capacitor?

While not strictly required for stability, a 0.33 µF ceramic capacitor placed ≤10 mm from Pin 1 (Input) to Pin 2 (Ground) is strongly recommended to suppress high-frequency noise and prevent oscillation during line transients. The datasheet shows improved ripple rejection and transient response with this capacitor in Figure 14 and Figure 15.

L78S05CV 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 FAQ

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

Please submit a Request for Quotation (RFQ) for L78S05CV 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 reliable?

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

3.What payment methods are accepted for L78S05CV?

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

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for L78S05CV?

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

Once your L78S05CV 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?

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

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

All L78S05CV 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 meets industry standards.

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

All L78S05CV units undergo pre-shipment inspection (PSI). If there is an issue with L78S05CV, 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 part is unused and in its original packaging.

Return procedure for L78S05CV:

1.Submit a request within 90 days.

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

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