L79L05ABZ

Overview

The L79L05ABZ is a three-terminal negative voltage regulator from the L79L series by STMicroelectronics, housed in a TO-92 package. It provides a fixed output voltage of -5 V with an output current capability up to 100 mA. The device features internal thermal overload and short-circuit protection. Electrical characteristics include a line regulation of 150 mV (VI = -7 to -20 V) and load regulation of 60 mV (IO = 1 to 100 mA). The quiescent current is typically 6 mA at 25°C. The maximum DC input voltage is -30 V for this output voltage range, and the operating junction temperature range extends from -40°C to +125°C.

Feature Summary

• Integrated thermal overload and short-circuit protection mechanisms ensure robust operation under fault conditions.
• Designed as a direct replacement for Zener diode/resistor combinations, offering significantly improved output impedance and lower noise.
• Requires no external components for basic regulation functionality, simplifying circuit design.

Applications

• Local or on-card negative voltage regulation
• Elimination of noise associated with single-point regulation systems
• Replacement for Zener diode/resistor networks requiring stable negative bias

Procurement Notes

Verify that the specific part number corresponds to the AB grade, which indicates the extended -40°C to +125°C operating temperature range, distinct from the AC or C grades. Confirm the TO-92 through-hole package configuration matches the board layout requirements. Ensure compatibility with the required -5 V output specification and 100 mA current limit for the target application.

Selection Notes

Select this component when a fixed negative voltage rail is required for low-current applications up to 100 mA. The AB suffix denotes industrial temperature performance suitable for environments ranging from -40°C to +125°C. Consider the thermal resistance characteristics if heat dissipation is a concern, as power dissipation is internally limited but dependent on ambient conditions and PCB copper area.

Part Context

This component belongs to the L79L00 series of three-terminal negative regulators. The series includes various fixed output voltages such as -6 V, -8 V, -9 V, -12 V, and -15 V. The L79L05ABZ specifically utilizes the TO-92 package variant, while other packages like SO-8 and SOT-89 are available within the same series family for different mounting and thermal requirements.

Replacement Considerations

Compatible substitutes within the same series include L79L05ACZ and L79L05CD, though these may differ in operating temperature ranges or package types. Verify that any alternative maintains the -5 V output and sufficient current handling for the specific design constraints.