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onsemi KA7812E
- Part No.:
- KA7812E
- Manufacturer:
- onsemi
- Package:
- TO-220-3
- Datasheet:
-
KA7812E.pdf
- Description:
- IC REG LINEAR 12V 1A TO220-3
- Quantity:
- Payment:
- Shipping:
Inventory:4,245
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Product details
Overview
KA7812E from ON Semiconductor is a fixed-output +12 V, 1 A positive linear voltage regulator in TO-220 package with thermal overload protection, short-circuit protection, and safe operating area (SOA) protection. It delivers stable DC power for industrial control logic, embedded microcontroller supply rails, and analog sensor conditioning circuits requiring low-noise, regulated 12 V.
For engineers reviewing the KA7812E datasheet, pinout, applications, or equivalent options, this page provides verified electrical specifications, thermal performance data, real-world load/line regulation behavior, and validated alternative options for legacy design continuity and BOM optimization.
Technical Context
The KA7812E implements a classic three-terminal series pass architecture with internal error amplifier, reference voltage generator, current-limiting circuitry, and thermal shutdown comparator. Its SOA protection actively limits power dissipation during transient overloads to prevent junction failure.
It operates across –40°C to +125°C junction temperature range with guaranteed output voltage tolerance of ±4% at 25°C and ±5% over full temperature/load range. Dropout voltage remains fixed at 2 V at 1 A, independent of input voltage within specified limits.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 12.0 V ±4% at 25°C; maintains regulation from 11.4 V to 12.6 V across –40°C to +125°C, 5 mA–1 A load, and 14.5–27 V input. |
| Maximum Output Current | 1 A continuous; peak current capability up to 2.2 A for short-duration transients without latch-up. |
| Dropout Voltage | 2 V at 1 A and 25°C - defines minimum headroom required between input and output for regulation. |
| Ripple Rejection | 55–71 dB at 120 Hz (15–25 V input), enabling effective suppression of rectified AC ripple in unregulated DC supplies. |
| Output Noise | 76 μV RMS (10 Hz–100 kHz), suitable for noise-sensitive analog front-ends and precision reference generation. |
| Thermal Resistance | Junction-to-case: 5°C/W (TO-220); requires ≥12 cm² of 2 oz copper pad or external heatsink for sustained 1 A operation at ambient >50°C. |
| Protection Features | Integrated thermal shutdown, short-circuit current limiting (~230 mA), and SOA protection - no external components needed for basic fault resilience. |
Pinout & Package
KA7812E is supplied in TO-220 (Dual Gauge) package with standard 3-pin configuration: Input (Pin 1), Ground (Pin 2), Output (Pin 3). The metal tab is electrically connected to Pin 2 (GND) and serves as primary thermal path.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Input) | Unregulated DC input supply connection | Accepts 14.5–27 V DC; must be decoupled with ≥0.33 μF ceramic capacitor close to pin to prevent oscillation. |
| 2 (GND) | Reference and return node for internal circuitry | Common ground for input, output, and internal bias networks; tab connection enables heatsinking and must be isolated if chassis ground is not GND. |
| 3 (Output) | Regulated +12 V output terminal | Delivers stable 12 V to load; requires ≥0.1 μF ceramic capacitor at pin to ensure stability under dynamic load conditions. |
Key Features
| Feature | Design Value |
|---|---|
| Fixed +12 V output | Eliminates need for external feedback resistors - simplifies layout and improves long-term voltage accuracy vs. adjustable regulators. |
| 1 A continuous output current | Supports direct powering of multiple logic ICs, small relays, or op-amp stages without external pass transistors. |
| Thermal shutdown with auto-recovery | Halts output when junction exceeds ~170°C and resumes regulation once cooled - prevents permanent damage during overheating events. |
| Short-circuit current limit | Clamps output to ~230 mA during hard shorts - protects both regulator and upstream supply without fuse dependency. |
| SOA protection | Monitors instantaneous VCE × IC product to prevent second breakdown in the series pass transistor during high-voltage/low-current transients. |
Applications
| Industrial Power Supply | Microcontroller System Rail |
|---|---|
|
Use Scenario: Regulating rectified 18 V AC-to-DC adapter output to clean +12 V for PLC I/O modules and relay drivers. IC Role / Device Role / Timing Role: Primary linear regulator providing isolated, low-noise DC rail for digital and electromechanical loads. Use Value: Delivers 1 A with <120 mV load regulation (250–750 mA) and 55 dB ripple rejection - eliminates need for post-regulation LC filtering. |
Use Scenario: Supplying +12 V to legacy 8-bit microcontrollers (e.g., PIC16F, 8051) and associated peripheral ICs on compact control boards. IC Role / Device Role / Timing Role: Main system voltage source ensuring stable core and I/O voltage across varying code execution profiles. Use Value: Maintains ±5% output accuracy over –40°C to +85°C ambient with only 2 V dropout - enables use with low-cost 15 V wall adapters. |
| Analog Sensor Interface | Legacy Equipment Retrofit |
|
Use Scenario: Powering precision op-amps and 12-bit ADCs in industrial temperature/pressure transmitters where supply noise directly impacts measurement resolution. IC Role / Device Role / Timing Role: Low-noise analog supply rail generator with dedicated decoupling path. Use Value: 76 μV RMS output noise (10 Hz–100 kHz) and 18 mΩ output impedance minimize signal corruption in 12-bit systems. |
Use Scenario: Direct replacement for obsolete 7812 variants in field-deployed test equipment, medical analyzers, and telecom line cards requiring drop-in compatibility. IC Role / Device Role / Timing Role: Pin- and function-compatible upgrade maintaining identical footprint, thermal profile, and electrical behavior. Use Value: Same TO-220 pinout, ±4% tolerance, and protection features as legacy Fairchild KA7812E - zero PCB or firmware changes required. |
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 |
|---|---|---|---|
| LM7812CT | Same 12 V output, 1 A rating, TO-220 package; ±4% tolerance; higher quiescent current (6–8 mA vs. KA7812E's 5.1–8.0 mA). | Identical pinout and protection features; slightly lower ripple rejection (50–65 dB) and higher noise (90 μV). | Preferred where TI qualification or dual-sourcing is mandated; verify thermal margin due to higher IQ. |
| MC7812CD2TR4 | ON Semiconductor part; same family lineage; ±2% output tolerance (tighter than KA7812E's ±4%), D2PAK package (surface-mount). | Not pin-compatible - requires PCB redesign; superior accuracy benefits precision analog systems but increases layout complexity. | Select when tighter initial accuracy and SMT assembly are priorities; avoid for through-hole legacy replacements. |
Compared with LM7812CT, KA7812E offers lower output noise and better ripple rejection; compared with MC7812CD2TR4, it provides proven through-hole reliability and drop-in compatibility for repair and retrofit, albeit with looser output tolerance.
Availability
KA7812E is available at Aetrix Electronics and suitable for industrial control systems, embedded microcontroller platforms, and analog sensor interface designs requiring stable component supply, long-lifecycle support, and consistent parametric performance across production batches.
Supply support for KA7812E 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 (formerly Fairchild Semiconductor) is a global semiconductor manufacturer specializing in power management, analog, and discrete devices for automotive, industrial, and cloud infrastructure markets.
The KA78XXE series was developed by Fairchild as a cost-optimized, robust 3-terminal linear regulator family for general-purpose DC power conversion - emphasizing reliability, integrated protection, and ease of use in legacy and new designs alike.
FAQ
What is the maximum input voltage for KA7812E?
The absolute maximum input voltage for KA7812E is 35 V when output is 12 V. However, the recommended operating range is 14.5 V to 27 V to maintain safe power dissipation and ensure reliable regulation. Exceeding 27 V significantly increases thermal stress and may trigger thermal shutdown under full load.
Does KA7812E require external capacitors?
Yes, KA7812E requires an input bypass capacitor (≥0.33 μF ceramic) and an output capacitor (≥0.1 μF ceramic) placed as close as possible to their respective pins. These capacitors stabilize the regulator, suppress high-frequency noise, and prevent oscillation - omission risks instability or erratic output behavior.
Is KA7812E pin-compatible with older 7812 regulators?
Yes, KA7812E uses the industry-standard TO-220 3-pin configuration (Input–GND–Output) and is fully pin-compatible with legacy 7812 variants including LM7812, MC7812, and original Fairchild μA7812. No PCB modifications are needed for direct replacement.
What thermal management is required for KA7812E at 1 A output?
At 1 A and 25°C ambient, KA7812E dissipates up to 14 W (e.g., 27 V in → 12 V out). With RθJC = 5°C/W, junction temperature rises ~70°C above case - requiring a heatsink or ≥12 cm² of 2 oz copper to keep TJ ≤125°C. Without heatsinking, continuous 1 A operation is limited to ambient ≤35°C.
How does KA7812E behave during short-circuit conditions?
Under short-circuit, KA7812E limits output current to approximately 230 mA and activates thermal shutdown if junction temperature exceeds ~170°C. Once cooled below the thermal threshold, it automatically recovers regulation - providing robust, self-protecting operation without external current-sense circuitry.
KA7812E 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):
- 12V
- 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
KA7812E FAQ
1.How can I place an order for KA7812E through Aetrix?
Please submit a Request for Quotation (RFQ) for KA7812E 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 KA7812E reliable?
The price and inventory of KA7812E are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KA7812E is usually 5 days.
3.What payment methods are accepted for KA7812E?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KA7812E transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for KA7812E?
KA7812E orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your KA7812E 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 KA7812E?
For technical support, including KA7812E datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KA7812E requirements.
6.How does Aetrix verify that KA7812E is sourced from the original manufacturer or authorized distributors?
All KA7812E 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 KA7812E meets industry standards.
7.What is the process for return or replacement of KA7812E?
All KA7812E units undergo pre-shipment inspection (PSI). If there is an issue with KA7812E, 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 KA7812E part is unused and in its original packaging.
Return procedure for KA7812E:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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