onsemi MC79L05ACDR2G: Fixed -5V Linear Voltage Regulator Datasheet and Application Circuit Design

The onsemi MC79L05ACDR2G is a classic fixed-output, negative voltage linear regulator belonging to the popular 79Lxx series. This device is engineered to deliver a stable -5V output at currents up to 100mA, making it an ideal solution for powering low-power analog circuitry, op-amp supplies, and as a secondary regulator in larger systems requiring a negative bias voltage. Its compact SOT-23 package offers a minimal footprint, crucial for modern, space-constrained PCB designs.

A thorough review of the datasheet is essential for successful implementation. Key parameters include an input voltage range of -7V to -20V, emphasizing that the input must be more negative than the output by a minimum dropout voltage. The device incorporates internal current limiting and thermal shutdown protection, safeguarding both the regulator and the load under fault conditions. Furthermore, its low standby current drain enhances efficiency in battery-powered applications.

The core of utilizing this IC lies in its application circuit design, which is notably straightforward. The basic configuration requires only two external components for operation, as illustrated in the manufacturer's datasheet:

1. Input Capacitor (C_IN): A 0.33μF capacitor placed close to the input pin is recommended to improve stability, particularly when the regulator is located at a distance from the power supply filter.

2. Output Capacitor (C_OUT): A 0.1μF capacitor at the output pin is sufficient to enhance transient response and ensure stability.

For improved performance, especially in environments with fluctuating loads or potential transients, larger capacitor values can be used. The circuit's simplicity is a significant advantage, allowing for a reliable and cost-effective power supply solution with a minimal bill of materials (BOM).

ICGOOODFIND: The onsemi MC79L05ACDR2G provides a robust and highly reliable method for generating a precise -5V rail from a higher negative input voltage. Its exceptional simplicity, built-in protection features, and compact form factor solidify its status as a fundamental component for countless analog and mixed-signal designs, offering engineers a trusted solution for negative voltage regulation.

Keywords: Negative Voltage Regulator, Linear Regulator, -5V Output, Application Circuit, Datasheet