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onsemi KA78R09CYDTU
- Part No.:
- KA78R09CYDTU
- Manufacturer:
- onsemi
- Package:
- TO-220-4 Full Pack, Formed Leads
- Datasheet:
-
KA78R09CYDTU.pdf
- Description:
- IC REG LINEAR 9V 1A TO220F-4L
- Quantity:
- Payment:
- Shipping:
Inventory:4,041
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Product details
Overview
KA78R09CYDTU from ON Semiconductor is a 1A, 9V fixed-output low-dropout linear voltage regulator in TO-220F-4L package with output disable control, thermal shutdown, and short-circuit protection. It delivers stable 9V power at up to 1A load with ≤0.5V dropout at full current, supporting industrial power rails where input-to-output differential is constrained. Used in embedded controllers requiring clean, enable-controlled 9V supply.
For engineers reviewing the KA78R09CYDTU datasheet, pinout, applications, or equivalent options, key selection criteria include disable-function timing, dropout under 1A load, thermal resistance (Rθjc = 4.31°C/W), and compatibility with standard TO-220 heatsinking solutions.
Technical Context
This regulator integrates bandgap reference, SOA protection, overvoltage detection, and disable-input logic to gate the pass transistor. The Vdis pin accepts TTL/CMOS-compatible logic levels (VdisH ≥ 2.0V, VdisL ≤ 0.8V) to enable or disable output without external switching.
Internal thermal shutdown activates at +150°C junction temperature, and peak current limiting responds within microseconds during overload. Dropout voltage remains ≤0.5V across -20°C to +80°C operating range at 1A, enabling use with 10–25V input sources.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 9.0V ±2.2% (8.78–9.22V), tightly regulated for 9V logic and analog subsystems |
| Max Output Current | 1.0A continuous - supports microcontroller cores, sensors, and interface ICs |
| Dropout Voltage | ≤0.5V at 1A - enables operation with only 10V input for reliable 9V output |
| Disable Threshold | VdisH ≥ 2.0V (enable), VdisL ≤ 0.8V (disable) - compatible with 3.3V/5V GPIO control |
| Ripple Rejection | 45–55dB @ 120Hz - suppresses AC line noise and switching supply ripple |
| Quiescent Current | ≤10mA at zero load - minimizes standby power in always-on systems |
| Thermal Resistance | Rθjc = 4.31°C/W - allows >10W dissipation with standard TO-220 heatsink |
Pinout & Package
TO-220F-4L full-mold plastic package with isolated tab; 4-pin vertical lead frame; pin 1 (Vin) and pin 4 (Vdis) on same side, pin 2 (Vo) and pin 3 (GND) on opposite side; tab electrically connected to GND.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - Vin | Input power supply connection | Accepts 10–25V DC input; must be decoupled near pin with ≥10μF capacitor |
| 2 - Vo | Regulated output terminal | Delivers 9V ±2.2% at up to 1A; requires ≥47μF output capacitor for stability |
| 3 - GND | Ground reference and thermal path | Common return for input/output; tab tied to this pin for heatsink mounting |
| 4 - Vdis | Enable/disable control input | Active-high logic: ≥2.0V enables output; ≤0.8V disables output and reduces quiescent current |
Key Features
| Feature | Design Value |
|---|---|
| Output Disable Function | Reduces quiescent current to <20μA when disabled, enabling low-power sleep modes |
| Thermal Shutdown Protection | Automatically disables output at Tj = +150°C and recovers after cooldown - prevents permanent damage |
| Short-Circuit & Overcurrent Limiting | Peak current limit protects against sustained shorts; foldback behavior limits power dissipation during fault |
| Low Dropout Operation | 0.5V max dropout at 1A allows use with minimal input headroom - ideal for battery-backed or multi-rail systems |
| Overvoltage Protection | Clamps internal node voltages during transient overvoltage events - improves system-level robustness |
Applications
| Industrial PLC I/O Module | Automotive Body Control Unit |
|---|---|
Use Scenario: Powering isolated digital I/O drivers and analog sensor interfaces in DIN-rail mounted PLC modules. IC Role / Device Role / Timing Role: Primary 9V rail regulator with enable control synchronized to module reset sequence. Use Value: Low dropout ensures stable 9V output even as 12V bus sags during cranking or brownout conditions. | Use Scenario: Supplying 9V to LIN transceivers and window lift motor controllers in door modules. IC Role / Device Role / Timing Role: Local point-of-load regulator with disable input tied to vehicle ignition state. Use Value: Vdis pin enables immediate shutdown during key-off, reducing parasitic drain below 20μA. |
| Medical Patient Monitor Front-End | Test & Measurement Equipment |
Use Scenario: Providing clean 9V bias for precision op-amps and ADC reference buffers in portable monitors. IC Role / Device Role / Timing Role: Low-noise, enable-controlled analog supply rail with tight output tolerance. Use Value: 45–55dB ripple rejection suppresses switching noise from adjacent DC-DC converters, preserving signal integrity. | Use Scenario: Powering FPGA configuration circuitry and EEPROMs in benchtop analyzers requiring sequenced power-up. IC Role / Device Role / Timing Role: Secondary 9V regulator controlled by system supervisor IC via Vdis pin. Use Value: Precise 9.0V ±2.2% output ensures reliable FPGA configuration voltage margin and EEPROM write endurance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar fixed-output LDO regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2940CT-9.0/NOPB | 1A output, 9V, TO-220-3; no disable pin; higher dropout (0.6V typ) | Lacks enable control; requires external MOSFET for shutdown | Choose when disable function is unnecessary and cost is primary constraint |
| TLV1117-90CDT | 800mA output, 9V, SOT-223; no disable pin; lower thermal capability (Rθja ≈ 60°C/W) | Lower current rating and no disable; unsuitable for 1A loads or remote enable | Choose only for space-constrained, sub-800mA applications without enable requirement |
Compared with LM2940CT-9.0/NOPB and TLV1117-90CDT, KA78R09CYDTU uniquely combines 1A current, 0.5V dropout, and integrated disable control in TO-220F-4L - enabling compact, enable-sequenced 9V rails without external components.
Availability
KA78R09CYDTU is available at Aetrix Electronics and suitable for industrial automation, automotive body electronics, medical instrumentation, and test equipment requiring stable component supply and long-term manufacturability.
Supply support for KA78R09CYDTU 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 energy-efficient power management, analog, and sensing solutions for automotive, industrial, and cloud infrastructure markets.
The KA78RXXC series was designed as a drop-in upgrade to legacy 78xx regulators, adding disable control and improved thermal performance while maintaining TO-220 compatibility for legacy designs.
FAQ
What is the maximum input voltage rating for KA78R09CYDTU?
The absolute maximum input voltage for KA78R09CYDTU is 35V. However, for reliable operation at 1A output, the recommended input range is 10V to 25V per the datasheet's electrical characteristics table - ensuring sufficient headroom for dropout while avoiding excessive power dissipation.
Does KA78R09CYDTU require an external output capacitor, and what value is recommended?
Yes, KA78R09CYDTU requires an external output capacitor for stability and transient response. The datasheet specifies Co > 47μF - a low-ESR electrolytic or polymer capacitor rated for ≥16V is recommended, placed as close as possible to pins 2 (Vo) and 3 (GND).
How does the disable function of KA78R09CYDTU behave during power-up?
KA78R09CYDTU powers up enabled by default: when Vdis is left floating or pulled high (>2.0V), output activates after internal startup delay (~100μs). To ensure controlled sequencing, tie Vdis to a known logic level (e.g., microcontroller GPIO) before applying Vin - the device will remain disabled until Vdis exceeds 2.0V.
Can KA78R09CYDTU be used without a heatsink?
KA78R09CYDTU can operate without a heatsink only at very low power dissipation - e.g., ≤1.5W (Pd1 rating). At 1A output with 12V input (3V dropout), power dissipation is ~3W, exceeding the no-heatsink limit. A heatsink is required for continuous 1A operation; Rθjc = 4.31°C/W enables safe thermal design with standard TO-220 clips.
What is the output voltage tolerance of KA78R09CYDTU over temperature and load?
KA78R09CYDTU guarantees output voltage of 8.78V to 9.22V (±2.2%) across full operating conditions: -20°C to +80°C ambient, 5mA to 1A load, and specified input range. This tolerance includes line regulation (≤2.5%), load regulation (≤2.0%), and temperature drift - verified per the Electrical Characteristics table.
KA78R09CYDTU Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- TO-220-4 Full Pack, Formed Leads
- 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):
- 0.5V @ 1A
- Current - Output:
- 1A
- Current - Quiescent (Iq):
- 10 mA
- Current - Supply (Max):
- -
- PSRR:
- -
- Control Features:
- Enable
- Protection Features:
- Over Current, Over Temperature, Over Voltage, Short Circuit
- Operating Temperature:
- -20°C ~ 80°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-220F-4L (Forming)
KA78R09CYDTU FAQ
1.How can I place an order for KA78R09CYDTU through Aetrix?
Please submit a Request for Quotation (RFQ) for KA78R09CYDTU 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 KA78R09CYDTU reliable?
The price and inventory of KA78R09CYDTU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KA78R09CYDTU is usually 5 days.
3.What payment methods are accepted for KA78R09CYDTU?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KA78R09CYDTU transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for KA78R09CYDTU?
KA78R09CYDTU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your KA78R09CYDTU 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 KA78R09CYDTU?
For technical support, including KA78R09CYDTU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KA78R09CYDTU requirements.
6.How does Aetrix verify that KA78R09CYDTU is sourced from the original manufacturer or authorized distributors?
All KA78R09CYDTU 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 KA78R09CYDTU meets industry standards.
7.What is the process for return or replacement of KA78R09CYDTU?
All KA78R09CYDTU units undergo pre-shipment inspection (PSI). If there is an issue with KA78R09CYDTU, 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 KA78R09CYDTU part is unused and in its original packaging.
Return procedure for KA78R09CYDTU:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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