MICROCHIP LR8N3-G Adjustable Linear Voltage Regulator TO-92-3

The MICROCHIP LR8N3-G is a versatile, 3-terminal high-voltage, low-output current adjustable linear voltage regulator, designed for robust industrial applications. It features an exceptionally wide operating input voltage range from 13.2V up to 450V, providing significant design flexibility. The output voltage is user-adjustable from 1.20V to 440V, with the key requirement that the input voltage exceeds the output voltage by at least 12V for stable operation.

Voltage adjustment is achieved using two simple external resistors (R1 and R2). The IC regulates the voltage difference between its VOUT and ADJ pins to a nominal 1.20V. This reference voltage is then amplified by the external resistor ratio. Additionally, an internal constant bias current of typically 10µA flows to the ADJ pin, which adds a small, fixed offset voltage to the output.

Key Features & Protection

The regulator incorporates essential protection mechanisms for reliable performance. It features output current limiting, with a typical limit of 20mA, ensuring that an output short-circuit condition will be safely constrained. Internal junction temperature limiting is also included, with a minimum activation threshold of 125°C, safeguarding the device from thermal overload.

With a compact TO-92-3 through-hole package, it is easy to integrate into prototypes and end products. It operates reliably across a broad temperature range from -40°C to +85°C, making it suitable for challenging environments. The device offers a 5% output voltage tolerance, balancing precision with robustness for power management tasks.

Applications

This linear regulator is ideal for applications requiring a stable, adjustable voltage from a high input source. Common uses include industrial control systems, motor drive control circuits, and general power management solutions where simplicity, reliability, and high-voltage capability are paramount.