L4979MD

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Overview

The L4979MD is an automotive-grade low dropout linear regulator featuring integrated microprocessor control functions, including a watchdog timer and low voltage reset. It operates within a DC supply voltage range of 5.6 V to 31 V, delivering a fixed 5 V output with up to 500 mA current capability. The device ensures high precision with +/-2% output voltage accuracy across wide temperature variations. Key electrical parameters include a typical quiescent current of 100 μA in enabled mode and 6 μA when disabled. It features internal thermal shutdown and short-circuit protection, operating reliably from -40 °C to +150 °C junction temperature.

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Feature Summary

• Integrated microprocessor supervision functions including programmable watchdog timer and low voltage reset circuit
• Automotive qualification compliant with AEC-Q100 standards for high reliability
• Ultra-low power consumption with distinct active and standby quiescent current modes
• Robust protection mechanisms against thermal overload and output short circuits

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Applications

• Microprocessor power supply units requiring integrated reset and watchdog capabilities
• Automotive electronic control units (ECUs) and infotainment systems
• Industrial control modules operating in harsh thermal environments
• Battery-powered systems requiring efficient low-dropout regulation

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Procurement Notes

Verify the specific suffix and package variant against the official STMicroelectronics datasheet to ensure compatibility with design requirements. Confirm AEC-Q100 qualification status if automotive compliance is mandatory. Check for moisture sensitivity levels and recommended soldering profiles prior to assembly. Ensure input voltage constraints are strictly observed to prevent device damage.

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Selection Notes

Select this component when a fixed 5 V rail is required alongside essential microprocessor monitoring features. It is suitable for designs needing high input voltage tolerance up to 31 V or 40 V depending on conditions. Consider the SOIC-20 package for surface mount applications. Evaluate the trade-off between linear regulation efficiency and the benefit of integrated system management functions compared to switching regulators.

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Part Context

The L4979MD belongs to the L4979 series of low dropout regulators designed specifically for automotive and industrial markets. This family integrates standard LDO functionality with advanced supervisory circuits, reducing the need for external components. The MD variant typically denotes specific packaging or automotive qualification grades within the broader product line, emphasizing reliability under extreme operating conditions.

Voltage Regulators - Linear, Low Drop Out (LDO) Regulators Replacement Considerations

Consult official STMicroelectronics documentation for direct pin-compatible substitutes within the L4979 series. Verify that any replacement maintains the same microprocessor control features and automotive qualification status. Cross-reference input/output voltage ranges and thermal characteristics to ensure functional equivalence.