STMicroelectronics

L79L05ABD

L79L05ABD Description

The L79L05ABD from STMicroelectronics is a fixed-output negative linear voltage regulator designed to deliver a stable -5V output with a maximum current of 100mA. Housed in an 8-pin SOIC package, this surface-mount IC is optimized for precision voltage regulation in low-power applications. It features over-temperature and short-circuit protection, ensuring robust operation under fault conditions. With a quiescent current of 5.5mA and a PSRR of 49dB (120Hz), it offers excellent noise rejection, making it suitable for sensitive analog circuits. Although marked as obsolete, it remains a reliable choice for legacy designs requiring a compact, RoHS3-compliant solution.

L79L05ABD Features

• Fixed Negative Output: Delivers a precise -5V with ±4% tolerance.
• Low Dropout: Operates efficiently with minimal headroom voltage.
• High PSRR (49dB): Superior noise suppression for clean power delivery.
• Protection Mechanisms: Built-in over-temperature and short-circuit safeguards.
• Low Quiescent Current (5.5mA): Enhances energy efficiency in battery-powered systems.
• Surface-Mount Design (SOIC-8): Saves board space in compact layouts.
• RoHS3 Compliant: Meets modern environmental standards.

L79L05ABD Applications

• Analog Signal Chains: Ideal for op-amp biasing and sensor interfaces requiring noise-free negative rails.
• Legacy Industrial Systems: Supports older control modules where -5V rails are critical.
• Portable Devices: Suitable for low-power audio circuits or portable test equipment.
• Power Management: Acts as a secondary regulator in mixed-voltage PCBs or dual-supply systems.

Conclusion of L79L05ABD

The L79L05ABD excels in providing stable, low-noise negative voltage regulation for precision electronics. Its high PSRR, protection features, and compact form factor make it a standout for legacy and niche applications, despite its obsolete status. Engineers valuing reliability and noise immunity in constrained designs will find this regulator a pragmatic solution. For new projects, consider modern alternatives, but for existing systems, the L79L05ABD remains a proven performer.