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

STMicroelectronics L78M09ACDT-TR

Name: L78M09ACDT-TR
Brand: STMicroelectronics
SKU: L78M09ACDT-TR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: L78M09ACDT-TR

Manufacturer:: STMicroelectronics

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

Package:: TO-252-3, DPAK (2 Leads + Tab), SC-63

Datasheet:: L78M09ACDT-TR.pdf

Description:: IC REG LINEAR 9V 500MA DPAK

Quantity:: RFQ Add To RFQ list

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Inventory:2,212

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Product details

Overview

L78M09ACDT-TR from STMicroelectronics is a fixed-output +9 V, 500 mA positive voltage regulator in DPAK package with ±2 % output voltage tolerance, thermal overload protection, short-circuit protection, and output transition SOA protection-designed for local on-card regulation in industrial power supplies and embedded control modules.

For engineers reviewing the L78M09ACDT-TR datasheet, L78M09ACDT-TR pinout, L78M09ACDT-TR application, or L78M09ACDT-TR equivalent, key selection criteria include guaranteed operation from 0 °C to +125 °C junction temperature, 2 V dropout voltage at 25 °C, 56 dB supply voltage rejection at 120 Hz, 52 µV output noise (10 Hz–100 kHz), and internal current limiting up to 700 mA peak.

Technical Context

This three-terminal linear regulator employs an internal pass transistor with safe-area compensation, enabling robust short-circuit survival without external components. Its architecture integrates thermal shutdown, foldback current limiting, and SOA protection-eliminating need for external current-sense or thermal monitoring circuitry in most applications.

The device operates with input voltages from 11.5 V to 24 V for nominal 9 V output, maintaining regulation across load currents from 5 mA to 500 mA and junction temperatures from 0 °C to +125 °C. It requires only 0.33 µF input and 0.1 µF output ceramic or tantalum capacitors for stable operation.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Voltage	+9.0 V ±2 % (8.82–9.18 V at 25 °C; 8.64–9.36 V over full load/temp range)
Output Current	500 mA continuous (internally limited; 700 mA peak short-circuit current)
Dropout Voltage	2.0 V at 25 °C (minimum VI = 11.5 V required for regulation at full load)
Supply Rejection	56 dB at 120 Hz (VI = 12.5–23 V, IO = 300 mA, TJ = 25 °C)
Output Noise	52 µV RMS (10 Hz–100 kHz bandwidth, TJ = 25 °C)
Operating Temp	0 °C to +125 °C junction (AC grade; excludes automotive or extended industrial extremes)
Quiescent Current	6 mA typical (±0.8 mA variation over VI = 11.5–25 V and IO = 200 mA)

Pinout & Package

Package: DPAK (TO-252), surface-mount, thermally enhanced plastic case with exposed drain pad for PCB heat sinking. Thermal resistance: R_thJC = 8 °C/W, R_thJA = 100 °C/W (standard JEDEC 2-layer board).

Pin/Terminal	Circuit Role	Design Meaning
1 (Input)	Voltage Input	Accepts unregulated DC input (11.5–24 V); requires ≥0.33 µF bypass capacitor placed adjacent to pin
2 (Ground)	Circuit Common	Reference node for output and internal regulation; must be low-impedance connection to minimize ground bounce
3 (Output)	Regulated Output	Delivers stable +9 V; requires ≥0.1 µF output capacitor; connects directly to load and feedback path

Key Features

Feature	Design Value
Thermal Overload Protection	Automatic shutdown at T_J > ~150 °C; resumes operation after cooldown-prevents permanent damage during sustained overload
Short-Circuit Current Limiting	250 mA typical continuous short-circuit current (700 mA peak); avoids fuse or external current-limiting resistor
SOA Compensation	Reduces safe operating area derating under high V_CE conditions-enables reliable operation even with large input-output differentials
±2 % Output Tolerance	Tight initial accuracy eliminates need for post-manufacturing trimming in cost-sensitive industrial power rails
Extended Temperature Range	Guaranteed performance from 0 °C to +125 °C junction-supports non-automotive industrial and telecom equipment without derating

Applications

Industrial PLC I/O Modules

Embedded Microcontroller Power Rails

Use Scenario: Local 9 V supply for analog sensor signal conditioning and digital I/O drivers in modular PLC backplanes.

IC Role / Device Role / Timing Role: Primary 9 V linear regulator delivering clean, low-noise power to op-amps, ADC references, and level-shifters.

Use Value: 52 µV output noise and 56 dB ripple rejection ensure <1 LSB error in 12-bit analog front-ends without additional filtering.

Use Scenario: Dedicated 9 V rail for MCU peripherals including CAN transceivers, UART level shifters, and EEPROM programming circuits.

IC Role / Device Role / Timing Role: Fixed-voltage local regulator decoupling microcontroller core logic from noisy system bus supplies.

Use Value: Internal thermal shutdown prevents latch-up during transient overloads caused by peripheral hot-plug events.

Point-of-Load Telecom Power

Test & Measurement Instrumentation

Use Scenario: Secondary 9 V supply in base station RF module power trees where EMI-sensitive analog sections require ultra-low noise.

IC Role / Device Role / Timing Role: Post-regulator cleaning up switching converter outputs before feeding RF bias networks and PLL VCOs.

Use Value: 2 V dropout enables efficient use of intermediate bus voltages (e.g., 12 V) while maintaining headroom for line/load regulation.

Use Scenario: Stable 9 V reference for precision DAC buffers and calibration circuitry in benchtop multimeters and signal generators.

IC Role / Device Role / Timing Role: Precision voltage source supporting metrology-grade analog subsystems requiring long-term stability.

Use Value: ±2 % output tolerance and –0.5 mV/°C drift enable direct use in 0.1 % accuracy measurement paths without recalibration.

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
LM78M09CDT-TR	±4 % output tolerance (vs. ±2 %), wider quiescent current variation (6–10 mA), no guaranteed AC-grade temp range	Not qualified for 0–125 °C operation; requires derating above 85 °C ambient	Select when cost sensitivity outweighs precision and extended temperature needs
MC78M09BDTG	TO-220 package (vs. DPAK), higher R_thJA (50 °C/W), same ±2 % tolerance but lower SVR (52 dB)	Requires heatsink for >300 mA loads; less suitable for dense SMT layouts	Select when through-hole assembly or legacy footprint compatibility is mandatory

Compared with LM78M09CDT-TR and MC78M09BDTG, L78M09ACDT-TR delivers tighter output accuracy, guaranteed high-temp operation without derating, and superior thermal performance in compact SMT form-making it optimal for space-constrained industrial controllers and instrumentation.

Availability

L78M09ACDT-TR is available at Aetrix Electronics and suitable for industrial PLC I/O modules, embedded microcontroller power rails, and point-of-load telecom power systems requiring stable component supply, long-lifecycle support, and traceable sourcing.

Supply support for L78M09ACDT-TR 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 silicon solutions for automotive, industrial, and consumer markets since 1987.

L78M09ACDT-TR belongs to the L78MxxAC precision linear regulator product line, engineered specifically for industrial-grade local regulation where reliability, thermal resilience, and tight output tolerance are critical in non-automotive embedded systems.

FAQ

What is the minimum input voltage required for L78M09ACDT-TR to maintain regulation at full 500 mA load?

The minimum input voltage is 11.5 V, based on the 2.0 V dropout specification at 25 °C and full load. At elevated junction temperatures or worst-case process corners, design margin recommends using ≥12 V input to ensure regulation across the full 0–125 °C operating range and 5–500 mA load span.

Can L78M09ACDT-TR be used in adjustable-voltage configurations?

Yes-by adding two external resistors to the ground pin per Figure 18 in the datasheet, the output can be adjusted from 7.0 V to 20 V. However, this configuration sacrifices the ±2 % factory-trimmed accuracy and requires careful layout to avoid noise injection into the feedback node.

Is an input bypass capacitor mandatory for stable operation?

Yes-a minimum 0.33 µF capacitor is required across the input pin and ground, placed with shortest possible leads. This suppresses high-frequency noise and prevents oscillation, especially when input traces exceed 2 cm or connect to switching supplies. Tantalum or ceramic types with low ESR are recommended.

Does L78M09ACDT-TR support reverse-polarity protection?

No-L78M09ACDT-TR lacks built-in reverse-voltage protection. Applying negative input voltage relative to ground may cause irreversible damage. An external series Schottky diode (e.g., 1N5819) on the input is required if reverse polarity exposure is possible in the system.

L78M09ACDT-TR Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: TO-252-3, DPAK (2 Leads + Tab), SC-63

Packaging:: Tape & Reel (TR)

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:: Surface Mount

Supplier Device Package:: DPAK

L78M09ACDT-TR FAQ

1.How can I place an order for L78M09ACDT-TR through Aetrix?

Please submit a Request for Quotation (RFQ) for L78M09ACDT-TR 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 L78M09ACDT-TR reliable?

The price and inventory of L78M09ACDT-TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L78M09ACDT-TR is usually 5 days.

3.What payment methods are accepted for L78M09ACDT-TR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L78M09ACDT-TR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for L78M09ACDT-TR?

L78M09ACDT-TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your L78M09ACDT-TR 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 L78M09ACDT-TR?

For technical support, including L78M09ACDT-TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L78M09ACDT-TR requirements.

6.How does Aetrix verify that L78M09ACDT-TR is sourced from the original manufacturer or authorized distributors?

All L78M09ACDT-TR 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 L78M09ACDT-TR meets industry standards.

7.What is the process for return or replacement of L78M09ACDT-TR?

All L78M09ACDT-TR units undergo pre-shipment inspection (PSI). If there is an issue with L78M09ACDT-TR, 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 L78M09ACDT-TR part is unused and in its original packaging.

Return procedure for L78M09ACDT-TR:

1.Submit a request within 90 days.

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

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