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onsemi LM7809ACT
- Part No.:
- LM7809ACT
- Manufacturer:
- onsemi
- Package:
- TO-220-3
- Datasheet:
-
LM7809ACT.pdf
- Description:
- IC REG LINEAR 9V 1A TO220-3
- Quantity:
- Payment:
- Shipping:
Inventory:4,156
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Product details
Overview
LM7809ACT from onsemi is a fixed +9.0 V, 1.0 A positive linear voltage regulator in TO-220 package with internal thermal shutdown, short-circuit current limiting, and safe-area compensation. It delivers stable output under input voltages from 11.5 V to 24 V and supports local on-card regulation in industrial power supplies and embedded control systems.
For engineers reviewing the LM7809ACT datasheet, pinout, applications, or equivalent options, key selection criteria include dropout voltage (2.0 V at 1.0 A), output voltage tolerance (±5% over load/temperature), ripple rejection (56 dB at 120 Hz), and thermal protection behavior under sustained 1.0 A load.
Technical Context
This monolithic IC uses a PNP pass transistor with built-in current limiting and thermal foldback. Its feedback loop maintains regulated output via internal bandgap reference and error amplifier, requiring no external components for basic operation.
The device operates across junction temperatures from −40°C to +150°C and sustains peak output current up to 2.2 A under transient conditions. Dropout is defined as VI − VO = 2.0 V at IO = 1.0 A and TJ = 25°C, with line regulation of ≤6.2 mV over 11.5–26 V input range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | +9.0 V nominal, ±5% over 5 mA–1.0 A load and −40°C to +125°C junction temperature |
| Max Output Current | 1.0 A continuous; 2.2 A peak for short transients without thermal derating |
| Input Voltage Range | 11.5 V to 24 V DC - minimum 2.0 V headroom required above output for regulation |
| Dropout Voltage | 2.0 V at 1.0 A and 25°C - dictates minimum input supply margin for stable regulation |
| Ripple Rejection | 56 dB at 120 Hz - suppresses AC ripple from unregulated DC sources like rectified mains |
| Quiescent Current | 3.4 mA typical - low bias draw enables efficient operation in standby-sensitive designs |
| Thermal Shutdown | Activates at TJ ≥ +150°C - protects die during overload or inadequate heatsinking |
Pinout & Package
LM7809ACT uses the standard TO-220 package (Case 221AB) with three leads: Pin 1 = Input, Pin 2 = Ground, Pin 3 = Output. The metal tab (heatsink surface) is internally connected to Pin 2 (Ground).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 | Input | Unregulated DC input supply; must exceed output by ≥2.0 V for regulation |
| Pin 2 | Ground | Common reference for input and output; also connects to heatsink tab |
| Pin 3 | Output | Stable +9.0 V regulated output; requires 0.33 µF input capacitor if remote from filter |
Key Features
| Feature | Design Value |
|---|---|
| No external components needed | Self-contained regulation with internal reference, error amp, and pass element - reduces BOM count and layout complexity |
| Internal short-circuit protection | Limits output current to ~0.2 A during fault - prevents damage during wiring errors or downstream shorts |
| Safe-area compensated pass transistor | Prevents second breakdown under high VI−VO stress - enables reliable operation at full current across wide input range |
| Thermal overload protection | Shuts down output when junction exceeds +150°C - avoids permanent silicon damage during sustained overload or poor heatsinking |
| Low output noise | 10 µV/V RMS (10 Hz–100 kHz) - suitable for analog circuits and low-noise sensor interfaces without added filtering |
Applications
| Industrial Power Supply | Embedded Control Module |
|---|---|
Use Scenario: Providing clean +9 V rail for PLC I/O modules powered from 24 VDC field bus. IC Role / Device Role / Timing Role: Primary local regulator converting 24 V system rail to isolated +9 V logic/sensor supply. Use Value: Eliminates need for external current limiting or thermal monitoring circuitry due to integrated protection features. | Use Scenario: Powering microcontroller peripherals (ADC, UART, GPIO) in automotive body control unit. IC Role / Device Role / Timing Role: Fixed-voltage LDO replacement for legacy 78xx-based subsystems requiring robust thermal response. Use Value: Maintains regulation through engine cranking dips (down to 11.5 V input) while surviving load dump transients via internal safe-area design. |
| Test Equipment Power Stage | Legacy System Retrofit |
Use Scenario: Biasing op-amps and precision references in bench multimeters and signal generators. IC Role / Device Role / Timing Role: Low-noise, stable voltage source for analog front-end circuitry. Use Value: 10 µV/V output noise and <1.5 mV load regulation ensure measurement accuracy unaffected by varying channel loads. | Use Scenario: Replacing obsolete 7809 variants in maintenance-replacement boards for factory automation hardware. IC Role / Device Role / Timing Role: Drop-in compatible fixed +9 V regulator with identical pinout and electrical behavior. Use Value: TO-220 footprint and identical thermal characteristics allow direct PCB reuse without layout changes or heatsink redesign. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar fixed positive voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM7809CDT | DPAK-3 package (surface-mount); same electrical specs but lower RJA (65°C/W vs. 92°C/W) | Better suited for automated assembly and space-constrained PCBs; requires reflow-compatible layout | Select when board area or manufacturing process favors SMT over through-hole TO-220 |
| NCV7809BDT | AEC-Q100 qualified; tighter output tolerance (±2% at 25°C); enhanced ESD rating (2 kV HBM) | Required for automotive under-hood applications where qualification and reliability margins are mandatory | Select for automotive-grade designs needing PPAP support and extended temperature validation |
Compared with LM7809ACT, LM7809CDT offers identical regulation performance in a smaller DPAK package for SMT production, while NCV7809BDT adds automotive qualification and tighter initial tolerance - neither is pin-compatible without footprint change, but both serve overlapping functional roles in different mechanical or compliance contexts.
Availability
LM7809ACT is available at Aetrix Electronics and suitable for industrial power supplies, embedded control modules, and test equipment requiring stable component supply with long-term lifecycle visibility and traceable sourcing.
Supply support for LM7809ACT 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
onsemi (formerly ON Semiconductor) is a global semiconductor supplier focused on energy-efficient electronics for automotive, industrial, cloud, and IoT applications.
The LM7800 series was designed as a cost-effective, robust fixed-voltage linear regulator family for local point-of-load regulation in harsh environments where simplicity, reliability, and integrated protection are critical.
FAQ
What is the minimum input voltage required for stable regulation with LM7809ACT?
The LM7809ACT requires a minimum input voltage of 11.5 V DC to maintain +9.0 V output under full 1.0 A load and across temperature. This corresponds to a 2.0 V dropout voltage at 25°C junction temperature. Input must remain ≥2.0 V above output even at the lowest point of ripple.
Does LM7809ACT require external capacitors for stability?
No, the LM7809ACT is internally compensated and does not require an output capacitor for stability. However, a 0.33 µF ceramic input capacitor is recommended if the regulator is located more than 6 inches from the main filter capacitor to prevent oscillation due to lead inductance.
How does thermal shutdown operate in LM7809ACT?
The LM7809ACT activates thermal shutdown when its junction temperature reaches +150°C, disabling the output until the die cools by ~15°C. This hysteresis prevents rapid cycling. Recovery occurs automatically once TJ drops below ~135°C, provided input voltage remains within specification.
Can LM7809ACT be used in adjustable configurations?
Yes, the LM7809ACT can be configured as an adjustable regulator using external resistors and a Zener diode, as shown in Figure 1 of the datasheet. However, this modifies the output voltage and may affect regulation accuracy, line/load regulation, and thermal performance compared to fixed-mode operation.
What is the output voltage tolerance of LM7809ACT over temperature and load?
The LM7809ACT guarantees ±5% output voltage tolerance over the full operating range: 5 mA to 1.0 A load, −40°C to +125°C junction temperature, and input voltage from 11.5 V to 24 V. At 25°C, typical tolerance is ±1.8% (8.82 V to 9.18 V) for the 'A' grade version.
LM7809ACT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- TO-220-3
- Packaging:
- Bulk
- 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:
- 1A
- Current - Quiescent (Iq):
- 8 mA
- Current - Supply (Max):
- -
- PSRR:
- 71dB (120Hz)
- Control Features:
- -
- Protection Features:
- Over Temperature, Short Circuit
- Operating Temperature:
- 0°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-220-3
LM7809ACT FAQ
1.How can I place an order for LM7809ACT through Aetrix?
Please submit a Request for Quotation (RFQ) for LM7809ACT 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 LM7809ACT reliable?
The price and inventory of LM7809ACT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM7809ACT is usually 5 days.
3.What payment methods are accepted for LM7809ACT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM7809ACT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM7809ACT?
LM7809ACT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM7809ACT 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 LM7809ACT?
For technical support, including LM7809ACT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM7809ACT requirements.
6.How does Aetrix verify that LM7809ACT is sourced from the original manufacturer or authorized distributors?
All LM7809ACT 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 LM7809ACT meets industry standards.
7.What is the process for return or replacement of LM7809ACT?
All LM7809ACT units undergo pre-shipment inspection (PSI). If there is an issue with LM7809ACT, 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 LM7809ACT part is unused and in its original packaging.
Return procedure for LM7809ACT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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