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

STMicroelectronics L78M09CV

Name: L78M09CV
Brand: STMicroelectronics
SKU: L78M09CV
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: L78M09CV

Manufacturer:: STMicroelectronics

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

Package:: TO-220-3

Datasheet:: L78M09CV.pdf

Description:: IC REG LINEAR 9V 500MA TO220AB

Quantity:: RFQ Add To RFQ list

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Inventory:7,145

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Product details

Overview

L78M09CV from STMicroelectronics is a three-terminal positive fixed-voltage linear regulator delivering 9 V at up to 500 mA output current, housed in a TO-220FP package with thermal overload, short-circuit, and safe operating area protection. It features ±4 % output voltage tolerance (C version), 2 V dropout voltage, and operates across 0 to 150 °C junction temperature range-used for local regulation in industrial power supplies, embedded controllers, and sensor interface modules.

For engineers reviewing the L78M09CV datasheet, L78M09CV pinout, L78M09CV application, or L78M09CV equivalent, key selection criteria include guaranteed 500 mA output under thermal constraints, input voltage range up to 35 V, line/load regulation performance, junction temperature limits, and compatibility with standard TO-220FP heatsinking solutions.

Technical Context

The L78M09CV implements a monolithic silicon pass transistor with internal current limiting, thermal shutdown, and SOA compensation-ensuring robust operation without external protection circuitry. Its architecture relies on a bandgap reference and error amplifier driving the series pass element, with no need for output capacitance for stability but benefitting from 0.1 µF ceramic output capacitance for transient response.

It operates as a drop-in replacement for legacy 78xx regulators while offering tighter thermal specification (0–150 °C) and improved safe-area protection. Input-to-output differential voltage must remain ≥2 V for regulation, and quiescent current remains stable at 6 mA across load and temperature ranges.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Voltage	9 V ±4 % (guaranteed over full temperature and load range-defines system rail accuracy)
Max Output Current	500 mA (sustained, with adequate heatsinking per R_thJC = 5 °C/W)
Dropout Voltage	2 V (minimum VI–VO required to maintain regulation-sets minimum input supply headroom)
Line Regulation	50 mV (VI change 12–25 V, IO = 200 mA-determines sensitivity to upstream supply ripple)
Load Regulation	90 mV (IO change 5–200 mA, TJ = 25 °C-defines output stability across dynamic load steps)
Supply Rejection	56 dB @ 120 Hz (VI = 12.5–23 V, IO = 300 mA-quantifies AC ripple attenuation capability)
Quiescent Current	6 mA (constant, independent of load-directly impacts no-load power loss)

Pinout & Package

TO-220FP (Full Pack) package: vertical mounting, insulated tab, 3-pin through-hole configuration with integrated heat sink pad. Requires mechanical isolation when mounted to heatsink due to electrically active tab.

Pin/Terminal	Circuit Role	Design Meaning
1 (Input)	Voltage input terminal	Accepts unregulated DC input (up to 35 V); requires 0.33 µF bypass capacitor near pin for high-frequency stability
2 (Ground)	Circuit common reference	Low-impedance return path for load and regulator control circuitry; must be routed with minimal trace inductance
3 (Output)	Regulated 9 V output	Delivers stabilized 9 V to load; benefits from 0.1 µF ceramic capacitor directly at pin for transient response

Key Features

Feature	Design Value
Thermal overload protection	Automatic shutdown at T_J > ~160 °C with hysteresis-prevents permanent damage during sustained overload or poor heatsinking
Short-circuit current limit	250 mA typical (VI = 35 V)-limits fault energy and enables safe recovery after overload removal
SOA-protected pass transistor	Internal compensation prevents secondary breakdown during high-V_CE/high-I_C transients-enables reliable operation without external foldback
Extended temperature range	0 to 150 °C operating junction range (C grade)-supports under-hood automotive and industrial environments
No external components required	Stable with only input/output capacitors-reduces BOM count and layout complexity vs. adjustable regulators

Applications

Industrial PLC I/O Module

Automotive Body Control Unit

Use Scenario: Powering isolated digital I/O drivers and analog sensor signal conditioning circuits within DIN-rail mounted programmable logic controllers.

IC Role / Device Role / Timing Role: Local 9 V rail generator providing clean, regulated supply for optocouplers, level shifters, and op-amps-decoupling noise from shared 24 V backplane.

Use Value: Eliminates need for centralized regulation and long PCB traces, reducing conducted EMI and improving immunity to bus voltage fluctuations.

Use Scenario: Supplying microcontroller peripherals (CAN transceivers, LIN drivers, EEPROM) in non-safety-critical body electronics modules.

IC Role / Device Role / Timing Role: Secondary 9 V regulator deriving from vehicle battery (12 V nominal), handling cold-crank dips and load-dump transients via upstream protection.

Use Value: Maintains functional operation down to 11.5 V input (per spec), enabling reliable boot and communication during engine start events.

Medical Patient Monitor Front-End

Point-of-Sale Terminal Power Management

Use Scenario: Generating stable 9 V for precision ADC references and low-noise analog front-end amplifiers in portable diagnostic devices.

IC Role / Device Role / Timing Role: Low-noise local regulator (58 µV RMS noise, 10 Hz–100 kHz) minimizing quantization error in 16-bit+ data acquisition paths.

Use Value: Achieves <0.01 % full-scale error contribution from supply noise-critical for clinical-grade measurement accuracy.

Use Scenario: Powering thermal print head drivers and secure element ICs in compact retail terminals with space-constrained PCB layouts.

IC Role / Device Role / Timing Role: Compact TO-220FP-mounted regulator delivering 500 mA peak current during print pulses while surviving 85 °C ambient enclosure temperatures.

Use Value: Enables direct heatsink mounting without isolation hardware, reducing bill-of-materials and assembly cost versus SMD alternatives.

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
LM7809CDT	Same 9 V output, ±2 % tolerance (A grade), TO-220 package, 0–125 °C range, higher quiescent current (8 mA)	Lacks extended temperature rating; lower thermal robustness in high-ambient designs	Select when tighter initial output accuracy is prioritized over high-temperature operation
MC78M09BDTG	9 V output, ±2 % (B grade), DPAK package, R_thJA = 100 °C/W, max 350 mA continuous output	Lower power handling; unsuitable for >350 mA loads without aggressive PCB copper pour	Choose for space-constrained SMT designs where 500 mA peak is not required

Compared with LM7809CDT and MC78M09BDTG, the L78M09CV offers superior thermal resilience (0–150 °C), higher guaranteed output current (500 mA), and lower quiescent current (6 mA), making it optimal for thermally demanding industrial and automotive applications where reliability under sustained load is critical.

Availability

L78M09CV is available at Aetrix Electronics and suitable for industrial automation systems, automotive body electronics, medical instrumentation, and point-of-sale terminals requiring stable component supply with long-term lifecycle support.

Supply support for L78M09CV 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 sensor solutions for industrial, automotive, and consumer markets.

The L78M series belongs to ST's precision 500 mA linear regulator product line, engineered for robust local regulation in harsh environments-emphasizing thermal survivability, intrinsic protection, and drop-in compatibility with legacy 78xx footprints.

FAQ

What is the maximum allowable input voltage for L78M09CV?

The absolute maximum DC input voltage is 35 V when regulating 9 V output, as specified in Table 1 of DS0425 Rev 24. Exceeding this risks permanent damage-even briefly-due to internal junction breakdown. For reliable operation, design input to stay ≤30 V with margin for ripple and transients.

Does L78M09CV require an input bypass capacitor?

Yes-a 0.33 µF or larger low-ESR capacitor (tantalum, ceramic, or film) is mandatory between input and ground, placed as close as possible to pins 1 and 2. This prevents high-frequency oscillation and ensures stability, especially with long input traces or upstream filter inductance.

Can L78M09CV be used in parallel for higher current?

No-L78M09CV lacks current-sharing capability and has no built-in ballasting. Parallel connection causes unequal current distribution due to output voltage tolerance (±4 %), leading to thermal runaway in the unit with lowest VO. Use a single higher-current regulator or external current-balancing circuitry instead.

Is the metal tab electrically connected to any pin?

Yes-the TO-220FP tab is internally connected to Pin 2 (Ground). Electrical isolation from heatsink is required unless the heatsink is grounded. ST recommends using insulating shoulder washers and isolated mounting hardware to prevent short circuits in floating-ground systems.

L78M09CV 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):: 9V

Voltage - Output (Max):: -

Voltage Dropout (Max):: -

Current - Output:: 500mA

Current - Quiescent (Iq):: 6 mA

Current - Supply (Max):: -

PSRR:: 56dB (120Hz)

Control Features:: -

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

Operating Temperature:: 0°C ~ 125°C

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: TO-220

L78M09CV FAQ

1.How can I place an order for L78M09CV through Aetrix?

Please submit a Request for Quotation (RFQ) for L78M09CV 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 L78M09CV reliable?

The price and inventory of L78M09CV are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L78M09CV is usually 5 days.

3.What payment methods are accepted for L78M09CV?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L78M09CV transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for L78M09CV?

L78M09CV orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your L78M09CV 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 L78M09CV?

For technical support, including L78M09CV datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L78M09CV requirements.

6.How does Aetrix verify that L78M09CV is sourced from the original manufacturer or authorized distributors?

All L78M09CV 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 L78M09CV meets industry standards.

7.What is the process for return or replacement of L78M09CV?

All L78M09CV units undergo pre-shipment inspection (PSI). If there is an issue with L78M09CV, 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 L78M09CV part is unused and in its original packaging.

Return procedure for L78M09CV:

1.Submit a request within 90 days.

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

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