Slkor SL7818: 18V 1A Positive‑Output Linear Regulator in TO‑220 Package

SL7818 is a three-terminal fixed positive-output linear regulator manufactured by Slkor in TO-220 package. It delivers fixed 18V output with maximum output current up to 1A. This IC integrates thermal-overload shutdown, short-circuit current limiting and output-transistor SOA protection and complies with RoHS requirements. Its operating input voltage ranges from 21V to 33V. Stable 18V DC output can be achieved with adequate heat dissipation for medium-and-small-power power-supply applications.

1. Core Product Parameters

Absolute Maximum Ratings

1. Maximum input voltage: 35V
2. Maximum output current: 1A
3. Power dissipation: Internally limited for TO-220 package; actual power dissipation depends on external thermal conditions
4. Maximum junction temperature: 150℃
5. Operating temperature range: -20℃ ~ 150℃
6. Storage temperature range: -55℃ ~ 150℃

Electrical Characteristics (Test condition: junction temperature at 25℃)

1. Output voltage: Typical value 18.0V; output voltage range 17.28V-18.72V under output current 5mA-1.0A; output voltage range 17.10V-18.90V with input voltage 21V-33V and output current 5mA-1.0A
2. Load regulation: Max. 180mV for output current 5mA-1.0A; max. 90mV for output current 0.25A-0.75A
3. Line regulation: Max.180mV within input voltage 21V-33V
4. Quiescent current: Max.8.0mA
5. Quiescent current variation: Max.1.0mA with input voltage 21.5V-33V; max.0.5mA for output current 5mA-1.0A
6. Output noise voltage: Typical 110µV within test frequency 10Hz-100kHz
7. Ripple rejection: Typical 69dB at 120Hz, input voltage 22V-32V
8. Typical peak output current:1.8A
9. Typical short-circuit current:250mA under input voltage 35V
10. Typical dropout voltage:2.0V

Package Information

Package type: TO-220 3-pin through-hole package.

2. Key Product Features

1. Fixed 18V positive regulated output with maximum 1A output current for medium-and-small-power DC power-supply demands.
2. Comprehensive built-in protections: thermal-overload shutdown activates when junction temperature exceeds threshold; short-circuit current limiting clamps output current during short-circuit events; output-transistor SOA protection prevents power-device damage beyond safe operating conditions.
3. RoHS-compliant for environmentally-friendly electronic-product designs.
4. Good ripple-rejection performance to attenuate AC ripple coupled from input side with controllable output noise.
5. TO-220 through-hole package supports external heat-sink mounting to greatly improve actual power-dissipation capacity.

3. Main Application Fields

1. High-efficiency linear regulator circuits providing stable 18V DC power supply.
2. Secondary post-regulation for switching power supplies for filtering and voltage stabilization of switch-mode power-supply outputs.
3. Power-supply circuits for micro-processors and peripherals requiring stable 18V supply.
4. On-board power modules on mainboards for local circuits requiring 18V power input.

4. Engineering Design Recommendations

1. Absolute-maximum ratings represent upper stress limits only. Long-term operation under absolute-maximum-rating conditions is prohibited. Exceeding these ratings will result in permanent device damage.
2. Practical steady-state output current is affected by input voltage, heat-sink specification, lead length and PCB copper-pad area. Proper heat-sink installation is mandatory for high-current scenarios to control junction temperature.
3. Input-side and output-side capacitors are recommended to improve transient response and suppress self-excited oscillation.
4. Typical dropout voltage is 2.0V. For normal regulation, input voltage shall exceed output voltage by at least 2.0V.
5. Valid operating input voltage range is 21V-33V. Input voltage shall never exceed 35V absolute-maximum rating to avoid chip damage caused by over-voltage.
6. Short-circuit protection serves as fault-protection mechanism. Continuous long-term output short-circuit is forbidden, as sustained short-circuit stress will shorten device service life.
7. PCB layout and soldering shall follow TO-220 mechanical dimensions. Reserve mounting space for heat sink and verify pin assignment to prevent device damage from mis-wiring.

5. Product Summary

SL7818 is a three-terminal fixed-18V positive linear regulator in TO-220 package, offering 1A output capacity plus multi-level protection for over-temperature, short-circuit and safe-operating-area constraints. It targets medium-and-small-power equipment requiring 18V DC supply, widely used for post-regulation of switching power supplies, micro-processor power feeding and local power loops on mainboards. In practical engineering projects, sufficient thermal design shall be implemented, input-output dropout requirement satisfied, input-voltage strictly limited and appropriate peripheral capacitors configured for long-term stable and reliable device operation.

About Slkor：

Slkor has research and development offices in Busan, South Korea, Beijing, China, and Suzhou, China. Most of the wafer manufacturing and packaging and testing are carried out within China. The company employs and collaborates with individuals and organizations worldwide, with a laboratory for product performance and reliability testing and a central warehouse located at its headquarters in Shenzhen. Slkor has filed for over a hundred invention patents, offers more than 2,000 product models, and serves over ten thousand customers globally. Its products are exported to countries and regions including Europe, the Americas, Southeast Asia, and the Middle East, making it one of the rapidly growing semiconductor companies in recent years. With well-established management systems and streamlined workflows, Slkor has rapidly enhanced the brand awareness and reputation of its "SLKOR" brand through its outstanding quality and standardized services. Its product range includes three major series: diodes, transistors, and power devices, with recent introductions of new products such as Hall elements and analog devices, expanding its presence in sensors, Risc-v microcontrollers, and other product categories.

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