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 L7809ACD2T

Name: L7809ACD2T
Brand: STMicroelectronics
SKU: L7809ACD2T
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: L7809ACD2T

Manufacturer:: STMicroelectronics

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

Package:: TO-263-3, D2PAK (2 Leads + Tab), TO-263AB

Datasheet:: L7809ACD2T.pdf

Description:: IC REG LINEAR 9V 1.5A D2PAK

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:2,301

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

Product details

Overview

L7809ACD2T from STMicroelectronics is a three-terminal positive linear voltage regulator delivering a fixed 9 V output with up to 1.5 A load current, ±2 % output voltage tolerance at 25 °C, thermal overload and short-circuit protection, and operation across 0 to 125 °C junction temperature - used for local regulation in industrial power supplies and embedded control modules.

For engineers reviewing the L7809ACD2T datasheet, L7809ACD2T pinout, L7809ACD2T application, or L7809ACD2T equivalent, this page provides verified electrical characteristics, TO-220FP package details, thermal resistance data (R_thJC = 5 °C/W), load/line regulation limits, and real-world substitution guidance for legacy 9 V linear regulator designs.

Technical Context

The L7809ACD2T implements a monolithic series-pass regulator architecture with internal current limiting, safe operating area (SOA) protection, and thermal shutdown circuitry - enabling robust operation without external protection components. Its design targets fixed-voltage local regulation where input-to-output differential remains ≥2 V under full load.

It operates with a minimum load current of 5 mA and supports input voltages up to 35 V (for VO = 9 V), with dropout voltage specified at 2 V @ 1 A and 25 °C. Ripple rejection is 61 dB at 120 Hz, and output noise is 10 µV/√Hz over 10 Hz–100 kHz.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Voltage	9 V ±2 % at 25 °C - ensures stable logic supply for 9 V-tolerant microcontrollers and analog subsystems
Max Output Current	1.5 A continuous - supports mid-power analog circuits and sensor interfaces without external pass devices
Dropout Voltage	2 V @ 1 A, 25 °C - requires minimum 11 V input for regulated 9 V output under full load
Line Regulation	5–45 mV over VI = 11–17 V - maintains tight output stability despite input rail variation
Load Regulation	10–100 mV over IO = 5 mA–1.5 A - minimizes voltage sag during dynamic load transients
Supply Rejection	61 dB @ 120 Hz - suppresses low-frequency ripple from unregulated DC sources or rectified AC
Thermal Resistance	R_thJC = 5 °C/W (TO-220FP) - enables >1 A operation with modest heatsinking

Pinout & Package

Package: TO-220FP - 3-pin, vertical mounting, insulated tab, plastic body with metal heat sink pad. Designed for PCB through-hole mounting and direct heatsink attachment via screw or clip.

Pin/Terminal	Circuit Role	Design Meaning
Pin 1 (Input)	V_IN	Unregulated DC input; must exceed VO + V_dropout (≥11 V) and remain ≤35 V
Pin 2 (Ground)	GND	Common reference for input and output; connects to system ground plane
Pin 3 (Output)	V_OUT	Regulated 9 V output; requires 0.1 µF ceramic capacitor (CO) close to pin for stability

Key Features

Feature	Design Value
Fixed 9 V output with 2 % tolerance	Guarantees compatibility with 9 V nominal systems without trimming or feedback resistors
Internal thermal shutdown	Prevents damage during sustained overload or inadequate heatsinking - auto-recovery on cooldown
Short-circuit current limit	Clamps output to ~0.4 A (L7809C) or ~0.2 A (L7809A) - protects against wiring faults and board shorts
SOA protection	Prevents transistor destruction during simultaneous high voltage and high current stress
Extended temperature range	0 to 125 °C operating junction - validated for industrial ambient environments

Applications

Industrial PLC I/O Module

Automotive Body Control Unit

Use Scenario: Powering isolated 9 V analog sensor inputs and digital level-shifters in DIN-rail mounted controllers.

IC Role / Device Role / Timing Role: Local point-of-load regulator providing clean, stable 9 V for op-amps and ADC references.

Use Value: Eliminates noise coupling from shared 24 V bus; thermal protection prevents field failure during enclosure overheating.

Use Scenario: Supplying 9 V to LIN transceivers and window motor drivers in door modules.

IC Role / Device Role / Timing Role: Fixed-voltage regulator interfacing between vehicle battery (9–16 V) and 9 V sub-systems.

Use Value: Withstands load dump transients up to 35 V input; short-circuit limit avoids fuse blowing during actuator stall.

Medical Infusion Pump Controller

Legacy Test Equipment Power Rail

Use Scenario: Generating 9 V for microcontroller peripherals and display backlight drivers in Class II medical devices.

IC Role / Device Role / Timing Role: Safety-isolated secondary-side regulator after transformer-based AC/DC conversion.

Use Value: 2 % tolerance ensures consistent timing in motor control loops; no external components reduce BOM count and certification burden.

Use Scenario: Replacing obsolete 7809 regulators in aging benchtop oscilloscopes and signal generators.

IC Role / Device Role / Timing Role: Direct drop-in replacement for legacy TO-220 9 V regulators with identical pinout and specs.

Use Value: Maintains original thermal profile (R_thJC = 5 °C/W) and ripple rejection (61 dB), ensuring unchanged measurement accuracy.

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/NOPB	±4 % output tolerance (vs. ±2 %), R_thJC = 5.5 °C/W, lower SVR (55 dB @ 120 Hz)	Higher output drift under load; less effective ripple suppression in noisy SMPS-derived inputs	Acceptable for cost-sensitive non-critical 9 V rails where tighter regulation is not required
MC7809BD2TR4G	±4 % tolerance, wider operating temp (−40 to 125 °C), higher quiescent current (8 mA vs. 4.3–6 mA)	Better cold-start performance but higher idle power draw in battery-backed systems	Preferred for automotive under-hood use; avoid in thermally constrained or low-quiescent designs

Compared with LM7809CDT/NOPB and MC7809BD2TR4G, the L7809ACD2T offers superior output accuracy and lower thermal resistance in the same TO-220FP footprint - making it optimal for industrial applications demanding long-term stability and thermal margin.

Availability

L7809ACD2T is available at Aetrix Electronics and suitable for industrial PLCs, automotive body control units, medical infusion pump controllers, and legacy test equipment requiring stable component supply and long-lifecycle support.

Supply support for L7809ACD2T 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 analog ICs for industrial, automotive, and consumer markets.

The L78 series is ST's flagship family of three-terminal positive linear regulators - engineered for reliability in harsh environments, with integrated protection and extended temperature grading for industrial and transportation applications.

FAQ

What is the minimum input voltage required for stable 9 V output at 1.5 A?

The L7809ACD2T requires a minimum input voltage of 11 V to maintain regulation at 1.5 A load, based on its 2 V dropout specification at 25 °C. At elevated junction temperatures, dropout increases slightly; design margin of ≥11.5 V is recommended for full-temperature operation.

Can L7809ACD2T be used without an input bypass capacitor?

No - STMicroelectronics specifies a minimum 0.33 µF ceramic capacitor (CI) between input and ground, placed within 1 cm of Pin 1. Omitting CI risks instability, oscillation, or poor transient response, especially with long input traces or high-impedance sources.

Is heatsinking mandatory for 1 A continuous operation?

Yes - while the TO-220FP package has R_thJC = 5 °C/W, junction temperature rises ~10 °C per watt dissipated. At 1 A with 3 V input–output differential (3 W), junction rise is ~15 °C above case. A heatsink keeping case ≤85 °C ensures safe operation within the 125 °C max junction rating.

Does L7809ACD2T support adjustable output voltage configurations?

Yes - though optimized as a fixed 9 V regulator, it can be configured as an adjustable regulator using external resistors per Figure 4 in DS0422. However, output accuracy, line/load regulation, and thermal performance degrade versus fixed-voltage mode due to added feedback path sensitivity and resistor tolerance effects.

L7809ACD2T Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: TO-263-3, D2PAK (2 Leads + Tab), TO-263AB

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):: 2V @ 1A (Typ)

Current - Output:: 1.5A

Current - Quiescent (Iq):: 6 mA

Current - Supply (Max):: -

PSRR:: 61dB (120Hz)

Control Features:: -

Protection Features:: Over Temperature, Short Circuit

Operating Temperature:: 0°C ~ 125°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: D2PAK

L7809ACD2T FAQ

1.How can I place an order for L7809ACD2T through Aetrix?

Please submit a Request for Quotation (RFQ) for L7809ACD2T 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 L7809ACD2T reliable?

The price and inventory of L7809ACD2T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L7809ACD2T is usually 5 days.

3.What payment methods are accepted for L7809ACD2T?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L7809ACD2T transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for L7809ACD2T?

L7809ACD2T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your L7809ACD2T 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 L7809ACD2T?

For technical support, including L7809ACD2T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L7809ACD2T requirements.

6.How does Aetrix verify that L7809ACD2T is sourced from the original manufacturer or authorized distributors?

All L7809ACD2T 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 L7809ACD2T meets industry standards.

7.What is the process for return or replacement of L7809ACD2T?

All L7809ACD2T units undergo pre-shipment inspection (PSI). If there is an issue with L7809ACD2T, 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 L7809ACD2T part is unused and in its original packaging.

Return procedure for L7809ACD2T:

1.Submit a request within 90 days.

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

Tech Hub

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 …

2026-08-28 SR Latch Explained: NOR and NAND Circuits, Truth Tables, and Applications

An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…

2026-08-27 Latch Circuit: SR and D Latches, Truth Tables, Timing, and Applications

Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…

2026-08-21 What Is an LED Driver? Types, Circuits, Dimming, and Selection

An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…

2026-08-18 Operational Amplifier (Op Amp): Basics, Configurations, Feedback and Applications

Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…