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onsemi KA7809ETSTU
- Part No.:
- KA7809ETSTU
- Manufacturer:
- onsemi
- Package:
- TO-220-3
- Datasheet:
-
KA7809ETSTU.pdf
- Description:
- IC REG LINEAR 9V 1A TO220-3
- Quantity:
- Payment:
- Shipping:
Inventory:1,384
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Product details
Overview
KA7809ETSTU from ON Semiconductor is a fixed-output +9 V, 1 A positive linear voltage regulator in TO-220 (dual-gauge) package with thermal overload, short-circuit, and safe operating area protection. It delivers stable DC power for industrial control logic, embedded microcontroller supply rails, and analog sensor conditioning circuits requiring low-noise, high-reliability regulation.
For engineers reviewing the KA7809ETSTU datasheet, pinout, applications, or equivalent options, key selection criteria include output voltage tolerance (±4%), dropout voltage (2 V at 1 A), ripple rejection (56–71 dB), thermal resistance (5 °C/W junction-to-case), and compatibility with standard 0.33 μF input / 0.1 μF output capacitor network.
Technical Context
The KA7809ETSTU implements a classic series-pass topology with internal error amplifier, reference voltage generator, current-limiting circuitry, and thermal shutdown comparator. Its SOA protection actively limits power dissipation during transient overloads without latch-up.
Designed for fixed-voltage operation, it does not require external feedback resistors but supports adjustable configurations via external pass transistors or resistor dividers. Input voltage range is 11.5 V to 24 V for guaranteed 9 V output under full 1 A load and ≤15 W power dissipation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | +9.00 V nominal, ±4% tolerance at 25°C (8.65–9.35 V); maintains regulation across -40°C to +125°C ambient |
| Max Output Current | 1 A continuous; peak current capability up to 2.2 A for short-duration transients |
| Dropout Voltage | 2 V at 1 A and 25°C - requires minimum 11 V input to sustain 9 V output under full load |
| Ripple Rejection | 56–71 dB at 120 Hz - suppresses AC line noise from unregulated DC supplies before regulation |
| Quiescent Current | 5–8 mA - enables low standby power in always-on systems without compromising regulation stability |
| Thermal Resistance | 5 °C/W junction-to-case - mandates heatsink for >0.5 A continuous operation at ambient >60°C |
| Output Noise | 58 μV RMS (10 Hz–100 kHz) - suitable for noise-sensitive analog front-ends and precision ADC references |
Pinout & Package
KA7809ETSTU uses the standard TO-220 (dual-gauge) package with three terminals: Input (Pin 1), Ground (Pin 2), Output (Pin 3). The metal tab is electrically connected to Pin 2 (GND) and serves as the primary thermal path to heatsink.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Input) | Unregulated DC supply input | Accepts 11.5–24 V DC; must be decoupled with ≥0.33 μF ceramic capacitor close to pin |
| 2 (GND) | Reference and return node | Common ground for input/output; metal tab is bonded to this pin - isolate from chassis unless grounded |
| 3 (Output) | Regulated +9 V DC output | Delivers up to 1 A; requires ≥0.1 μF ceramic capacitor at pin for stability and transient response |
Key Features
| Feature | Design Value |
|---|---|
| Thermal Overload Protection | Shuts down output when junction temperature exceeds ~170°C; auto-recovers after cooldown - prevents permanent damage during sustained overload |
| Short-Circuit Protection | Limits output current to ~250 mA during hard short - avoids fuse blowing and PCB trace damage in fault conditions |
| SOA Protection | Monitors VCE × IC product in pass transistor - prevents second breakdown during high-voltage/low-current transients |
| Fixed +9 V Output | No external components required for regulation - reduces BOM count and layout complexity vs. adjustable regulators |
| Wide Operating Temp | -40°C to +125°C case temperature range - qualified for industrial and automotive under-hood environments |
Applications
| Industrial PLC I/O Module | Automotive Body Control Unit |
|---|---|
Use Scenario: Powering digital isolators, optocouplers, and level-shifters in 24 V-powered programmable logic controller backplanes. IC Role / Device Role / Timing Role: Primary +9 V rail generator for interface ICs requiring clean, stable supply independent of main 5 V or 3.3 V logic rails. Use Value: Eliminates need for isolated DC-DC converters by providing regulated +9 V directly from 24 V bus with <2 V dropout and 56+ dB ripple rejection. | Use Scenario: Supplying microcontroller peripherals (CAN transceivers, LIN drivers, EEPROM) in vehicle door modules and seat controllers. IC Role / Device Role / Timing Role: Local point-of-load regulator converting battery-derived 12 V (8–16 V range) to stable +9 V for analog sensor interfaces and communication PHYs. Use Value: Maintains regulation down to 11.5 V input - supports cold-crank operation while delivering 1 A with thermal shutdown at 125°C ambient. |
| Medical Patient Monitor Sensor Interface | Test & Measurement Equipment Power Subsystem |
Use Scenario: Biasing precision op-amps and ADC drivers in portable ECG/SpO₂ front-end signal chains. IC Role / Device Role / Timing Role: Low-noise analog supply rail generator placed adjacent to sensitive analog components to minimize coupling. Use Value: 58 μV RMS output noise and 17 mΩ effective output impedance ensure minimal SNR degradation in 16-bit+ data acquisition paths. | Use Scenario: Providing auxiliary +9 V for calibration reference circuits, DAC buffers, and analog switch arrays in benchtop multimeters and signal generators. IC Role / Device Role / Timing Role: Secondary regulated rail supporting precision analog functions where switching noise from main SMPS must be avoided. Use Value: Ripple rejection >65 dB at 120 Hz rejects mains-synchronous artifacts from transformer-rectifier inputs, enabling sub-μV-level offset stability. |
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 |
|---|---|---|---|
| LM7809CT | Same +9 V output, ±4% tolerance, TO-220 package; higher quiescent current (6–10 mA) and lower ripple rejection (50–65 dB) | Less suitable for ultra-low-power or high-ripple-suppression applications; identical pinout and footprint | Select LM7809CT only if legacy design reuse or dual-sourcing with TI-based BOMs is required |
| MC7809CT | Identical electrical specs and TO-220 package; manufactured by ON Semiconductor (formerly Motorola); same thermal performance (5 °C/W) | No functional difference - direct second-source part with identical qualification and reliability data | MC7809CT is a functionally identical, drop-in replacement with identical lifecycle and documentation support |
Compared with LM7809CT, KA7809ETSTU offers superior ripple rejection and lower quiescent current; versus MC7809CT, it shares identical specifications and is a rebranded variant within the same ON Semiconductor product family.
Availability
KA7809ETSTU is available at Aetrix Electronics and suitable for industrial automation, automotive electronics, and medical instrumentation requiring stable component supply with long-term manufacturability and consistent parametric performance.
Supply support for KA7809ETSTU 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
ON Semiconductor is a global semiconductor manufacturer specializing in power management, analog, sensor, and connectivity solutions for automotive, industrial, cloud, and medical markets.
The KA78XXE series belongs to ON Semiconductor's legacy linear regulator portfolio, designed specifically for cost-sensitive, high-reliability fixed-voltage applications where simplicity, robustness, and wide temperature operation are critical.
FAQ
What is the maximum input voltage rating for KA7809ETSTU?
The absolute maximum input voltage for KA7809ETSTU is 40 V when configured for 24 V output variants, but for the +9 V version, the datasheet specifies 35 V as the safe limit. Operation above 24 V input is permissible only if power dissipation remains within 15 W and thermal design accommodates junction temperatures below 125°C. Always verify with the KA7809ETSTU Absolute Maximum Ratings table.
Does KA7809ETSTU require external capacitors, and what values are recommended?
Yes, KA7809ETSTU requires an input capacitor (≥0.33 μF ceramic) and output capacitor (≥0.1 μF ceramic) placed as close as possible to their respective pins. These stabilize the regulator against oscillation and improve transient response. Larger bulk capacitance (e.g., 470 μF electrolytic) may be added in parallel on the output for high-current pulsed loads, but the ceramic caps are mandatory per the KA7809ETSTU test circuit.
Is KA7809ETSTU pin-compatible with other 78xx-series regulators like KA7805ETU or KA7812ETU?
Yes, KA7809ETSTU is fully pin-compatible with all members of the KA78XXE family in TO-220 package, including KA7805ETU and KA7812ETU. All share identical pin 1 (Input), pin 2 (GND), pin 3 (Output) assignment and mechanical footprint - enabling board-level voltage rail swaps without layout changes.
What is the typical output voltage drift over temperature for KA7809ETSTU?
The KA7809ETSTU exhibits an output voltage drift of -1 mV/°C (typical) over temperature when loaded with 5 mA. This means the output decreases by approximately 1 mV for every 1°C rise in junction temperature - a key parameter for precision analog designs where long-term thermal stability matters. Full characterization is provided in the KA7809ETSTU Electrical Characteristics table.
Can KA7809ETSTU be used in adjustable voltage configurations?
Yes, KA7809ETSTU can be adapted for adjustable output using external components such as a series pass transistor and voltage divider, though it is optimized for fixed +9 V operation. Unlike LM317, it lacks an ADJ pin; therefore, adjustment requires external circuitry that modifies the reference or feedback path - detailed in Fairchild AN-550 and confirmed in KA7809ETSTU application notes.
KA7809ETSTU Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- 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):
- 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:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-220-3
KA7809ETSTU FAQ
1.How can I place an order for KA7809ETSTU through Aetrix?
Please submit a Request for Quotation (RFQ) for KA7809ETSTU 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 KA7809ETSTU reliable?
The price and inventory of KA7809ETSTU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KA7809ETSTU is usually 5 days.
3.What payment methods are accepted for KA7809ETSTU?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KA7809ETSTU transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for KA7809ETSTU?
KA7809ETSTU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your KA7809ETSTU 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 KA7809ETSTU?
For technical support, including KA7809ETSTU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KA7809ETSTU requirements.
6.How does Aetrix verify that KA7809ETSTU is sourced from the original manufacturer or authorized distributors?
All KA7809ETSTU 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 KA7809ETSTU meets industry standards.
7.What is the process for return or replacement of KA7809ETSTU?
All KA7809ETSTU units undergo pre-shipment inspection (PSI). If there is an issue with KA7809ETSTU, 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 KA7809ETSTU part is unused and in its original packaging.
Return procedure for KA7809ETSTU:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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