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

STMicroelectronics L78L09CD13TR

Name: L78L09CD13TR
Brand: STMicroelectronics
SKU: L78L09CD13TR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: L78L09CD13TR

Manufacturer:: STMicroelectronics

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

Package:: 8-SOIC (0.154", 3.90mm Width)

Datasheet:: L78L09CD13TR.pdf

Description:: IC REG LINEAR 9V 100MA 8SO

Quantity:: RFQ Add To RFQ list

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Product details

Overview

L78L09CD13TR from STMicroelectronics is a three-terminal positive linear voltage regulator delivering a fixed 9 V output at up to 100 mA, featuring internal current limiting, thermal overload protection, and short-circuit protection. It requires no external components, operates with input voltages up to 30 V (for 9 V output), and is specified for 0–125 °C junction temperature range in the SO-8 package. It serves as a local on-card regulator in industrial control modules and embedded power rails where low-noise, stable DC supply is critical.

For engineers reviewing the L78L09CD13TR datasheet, L78L09CD13TR pinout, L78L09CD13TR application, or L78L09CD13TR equivalent, key selection considerations include its ±4% output tolerance (C grade), 1.7 V dropout voltage at 40 mA, 70 µV RMS output noise (10 Hz–100 kHz), 37–44 dB supply voltage rejection at 120 Hz, and SO-8 thermal performance with R_thJA = 55 °C/W (with 6 cm² copper heat-sink).

Technical Context

The L78L09CD13TR implements a monolithic silicon-based series pass regulator architecture with built-in foldback current limiting and thermal shutdown circuitry-enabling robust operation without external protection components. Its internal bandgap reference and error amplifier maintain output regulation across load (1–100 mA) and line (11.5–23 V input) variations.

Designed for fixed-voltage local regulation, it replaces discrete Zener/resistor networks with lower quiescent current (6 mA typ. at 25 °C), improved load/line regulation (40 mV and 150 mV respectively), and tighter output accuracy (±4% over temperature). The SO-8 package integrates pins 2, 3, 6, and 7 to the die attach flag for enhanced thermal dissipation.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Voltage	9.0 V ±4% (min 8.64 V, max 9.36 V at 25 °C); ensures stable logic-level rail for microcontrollers and analog sensors.
Max Output Current	100 mA continuous; sufficient for powering small peripherals, op-amps, or interface ICs without external pass devices.
Dropout Voltage	1.7 V at 40 mA; enables operation from 10.7 V minimum input, supporting 12 V nominal systems with margin.
Supply Voltage Rejection	37–44 dB at 120 Hz; suppresses ripple from unregulated wall adapters or switching pre-regulators.
Output Noise	70 µV RMS (10 Hz–100 kHz); low enough for noise-sensitive analog front-ends like ADC references or sensor signal chains.
Quiescent Current	6 mA typical at 25 °C; enables efficient standby operation in battery-backed or low-power monitoring circuits.
Thermal Resistance	R_thJA = 55 °C/W (with 6 cm² PCB copper); allows ~1.1 W power dissipation before thermal shutdown under typical layout conditions.

Pinout & Package

Package: SO-8 (small outline integrated circuit, 8-pin, surface-mount), ECOPACK® compliant, with pins 2, 3, 6, and 7 internally connected to the die attach flag for improved thermal conduction to PCB copper.

Pin/Terminal	Circuit Role	Design Meaning
Pin 1 (Input)	V_IN	Unregulated DC input (11.5–23 V); must be decoupled with ≥0.33 µF ceramic capacitor close to pin.
Pin 2 (Ground)	GND	Common reference for input and output; electrically tied to die flag for thermal path and low-impedance return.
Pin 3 (Output)	V_OUT	Regulated +9 V output; requires ≥0.1 µF ceramic capacitor at pin for stability and transient response.
Pins 4, 5, 7, 8	No Connect / Flag Tie	Internally bonded to die attach flag; must be soldered to large copper pour for thermal management and EMI reduction.

Key Features

Feature	Design Value
Fixed-output voltage	9.0 V ±4% (C-grade), eliminating need for external feedback resistors and reducing BOM count.
Integrated protection	Thermal shutdown and short-circuit current limiting prevent damage during fault conditions without external circuitry.
No external components required	Stable operation with only input (0.33 µF) and output (0.1 µF) ceramic capacitors-reducing board space and cost.
Low quiescent current	6 mA typical at 25 °C, enabling use in always-on monitoring nodes where standby power matters.
SO-8 thermal enhancement	Internally connected flag pins reduce R_thJA to 55 °C/W (vs. 200 °C/W for TO-92), supporting higher ambient temperatures in compact designs.

Applications

Industrial PLC I/O Module

Automotive Body Control Unit (BCU)

Use Scenario: Powering isolated digital input buffers and CAN transceiver bias rails in DIN-rail mounted programmable logic controllers.

IC Role / Device Role / Timing Role: Local 9 V regulator supplying clean, protected voltage to optocoupler drivers and level-shifting logic.

Use Value: Eliminates noise coupling from shared 24 V bus while maintaining immunity to load dump transients via built-in short-circuit protection.

Use Scenario: Providing regulated 9 V supply to interior lighting controllers and door module microcontrollers in 12 V automotive systems.

IC Role / Device Role / Timing Role: Fixed-voltage post-regulator after buck converter, ensuring stable MCU core voltage despite battery voltage sag.

Use Value: Delivers 100 mA with 1.7 V dropout-operating reliably down to 10.7 V input during cranking events.

Medical Patient Monitor Sensor Interface

Smart Energy Meter Communication Subsystem

Use Scenario: Biasing analog front-end amplifiers and 16-bit ADC references in portable vital sign monitors.

IC Role / Device Role / Timing Role: Low-noise local regulator for precision analog signal chain, decoupled from noisy digital domains.

Use Value: 70 µV RMS output noise and 44 dB SVR ensure <0.01% measurement error in ECG/SpO₂ signal acquisition.

Use Scenario: Supplying 9 V to RS-485 transceivers and PLC communication modems in utility-grade electricity meters.

IC Role / Device Role / Timing Role: Isolated auxiliary rail generator for differential bus interfaces requiring galvanic separation and ESD robustness.

Use Value: Internal thermal shutdown prevents latch-up during surge events on long communication lines, improving field reliability.

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
LM78L09ACZ/NOPB	TO-92 package, R_thJA ≈ 200 °C/W, ±5% tolerance, 2 V dropout, 40 µV noise.	Lower thermal capability limits continuous 100 mA use without heatsink; suited for low-power, space-constrained through-hole designs.	Choose when legacy TO-92 footprint or lower cost outweighs thermal performance and noise requirements.
TL78L09ACDR	SO-8 package, ±5% tolerance, 2 V dropout, 100 µV noise, no internal thermal flag connection.	Higher noise and weaker SVR (32 dB) limit use in precision analog; lacks SO-8 thermal enhancement of L78L09CD13TR.	Prefer only if TI's qualification pedigree or existing supply chain alignment justifies trade-offs in noise and thermal design margin.

Compared with LM78L09ACZ/NOPB and TL78L09ACDR, the L78L09CD13TR offers superior thermal performance in SO-8, tighter ±4% output tolerance, lower 70 µV noise, and integrated flag bonding-making it optimal for high-reliability, noise-sensitive, surface-mount industrial applications demanding full 100 mA capability.

Availability

L78L09CD13TR is available at Aetrix Electronics and suitable for industrial PLCs, automotive body control units, medical sensor interfaces, and smart energy meter communication subsystems requiring stable component supply with guaranteed long-term manufacturability.

Supply support for L78L09CD13TR 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, and analog/mixed-signal devices for industrial, automotive, and consumer markets.

The L78L series belongs to ST's legacy linear regulator product line, engineered specifically for cost-effective, robust local regulation in space- and reliability-constrained embedded systems-emphasizing simplicity, protection integration, and wide-temperature operation.

FAQ

What is the maximum input voltage for L78L09CD13TR?

The absolute maximum DC input voltage is 30 V when regulating to 9 V output, per STMicroelectronics' DS0424 Rev 30 (page 4). Operation above this risks permanent damage. For reliable long-term use, ST recommends limiting input to ≤23 V under normal conditions to maintain thermal margin and ensure 100 mA output capability.

Does L78L09CD13TR require input and output capacitors?

Yes-ST specifies a minimum 0.33 µF ceramic capacitor at the input pin and 0.1 µF ceramic capacitor at the output pin for stability and transient response, as shown in Figure 13 of DS0424. Omitting either capacitor may cause oscillation or poor load regulation, especially under fast load steps or high source impedance.

Can L78L09CD13TR be used in automotive applications?

Yes-the L78L09CD13TR is rated for 0–125 °C operating junction temperature and features thermal shutdown and short-circuit protection, making it suitable for under-hood and cabin automotive subsystems such as body control modules and sensor interfaces. However, it is not AEC-Q100 qualified; for safety-critical applications, ST's AEC-Q100-compliant L78LxxAB variants should be selected.

How does the SO-8 package improve thermal performance over TO-92?

The SO-8 package of L78L09CD13TR connects pins 2, 3, 6, and 7 directly to the die attach flag, reducing thermal resistance to 55 °C/W (with 6 cm² PCB copper) versus 200 °C/W for TO-92. This allows ~1.1 W power dissipation before thermal shutdown-enabling full 100 mA output at higher ambient temperatures without external heatsinks.

L78L09CD13TR Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: 8-SOIC (0.154", 3.90mm Width)

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Output Configuration:: Positive

Output Type:: Fixed

Number of Regulators:: 1

Voltage - Input (Max):: 30V

Voltage - Output (Min/Fixed):: 9V

Voltage - Output (Max):: -

Voltage Dropout (Max):: -

Current - Output:: 100mA

Current - Quiescent (Iq):: 5.5 mA

Current - Supply (Max):: 6 mA

PSRR:: 44dB (120Hz)

Control Features:: -

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

Operating Temperature:: 0°C ~ 125°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 8-SOIC

L78L09CD13TR FAQ

1.How can I place an order for L78L09CD13TR through Aetrix?

Please submit a Request for Quotation (RFQ) for L78L09CD13TR 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 L78L09CD13TR reliable?

The price and inventory of L78L09CD13TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L78L09CD13TR is usually 5 days.

3.What payment methods are accepted for L78L09CD13TR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L78L09CD13TR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for L78L09CD13TR?

L78L09CD13TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your L78L09CD13TR 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 L78L09CD13TR?

For technical support, including L78L09CD13TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L78L09CD13TR requirements.

6.How does Aetrix verify that L78L09CD13TR is sourced from the original manufacturer or authorized distributors?

All L78L09CD13TR 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 L78L09CD13TR meets industry standards.

7.What is the process for return or replacement of L78L09CD13TR?

All L78L09CD13TR units undergo pre-shipment inspection (PSI). If there is an issue with L78L09CD13TR, 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 L78L09CD13TR part is unused and in its original packaging.

Return procedure for L78L09CD13TR:

1.Submit a request within 90 days.

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

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