L4979D

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

The L4979D is a low dropout linear regulator from STMicroelectronics, designed for automotive applications with AEC-Q100 qualification. It integrates microprocessor control functions including a low voltage reset circuit and a programmable watchdog timer. The device operates within an input voltage range of 5.6 V to 31 V, delivering a fixed output voltage with high precision. Key electrical characteristics include a maximum input voltage of 40 V, a typical quiescent current of 100 μA in enabled mode, and a shutdown current of 6 μA. It features thermal shutdown and short-circuit protection, operating reliably across the automotive temperature range of -40 °C to +150 °C.

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

• Integrates microprocessor supervision functions including a low voltage reset circuit and a programmable watchdog timer.
• Provides high output voltage accuracy maintained over wide temperature, line, and load variations.
• Features ultra-low power consumption with a typical quiescent current of 100 μA and 6 μA in shutdown mode.
• Includes comprehensive protection mechanisms such as thermal shutdown and internal current limiting.

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

• Automotive electronic systems requiring qualified power management components
• Microprocessor supply circuits needing integrated reset and watchdog capabilities
• Battery-powered automotive modules requiring low standby current consumption

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

Verify the specific suffix (e.g., D vs MD) against the official datasheet to confirm package type and exact parameter tolerances. Ensure the selected variant meets the required automotive qualification standards and operating temperature range for the target application environment.

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

Select this component when a single-channel LDO with integrated supervisor functions is required. It is suitable for designs needing precise voltage regulation with minimal external components. Consider the input-output voltage differential to ensure operation remains within the specified dropout voltage limits under all load conditions.

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

The L4979D belongs to the L4979 series of low dropout regulators manufactured by STMicroelectronics. This family is specifically engineered for automotive environments, offering robust performance and reliability. The series combines standard linear regulation with essential system monitoring features, simplifying the design of complex electronic control units.

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

What are the primary supervisory functions integrated into the L4979D?

The L4979D integrates a low voltage reset circuit that senses the output voltage down to 1 V and a programmable watchdog timer, both configurable with external capacitors.

How does the L4979D manage power consumption during inactive states?

The device achieves a very low quiescent current of 100 μA when enabled and reduces further to 6 μA when the enable input is set to a low state.