L9777B

Overview

The L9777B is a monolithic integrated low-dropout regulator from STMicroelectronics, designed for automotive microprocessor systems. It provides a primary output of up to 200 mA and an auxiliary output of 50 mA. The device operates within a DC supply voltage range of 5.6 V to 31 V and features high precision output voltage regulation with a tolerance of 2%. It includes a VDD tracking regulator switchable via the VDD_EN pin and a reset circuit capable of sensing output voltages down to 1 V. The component supports adjustable reset thresholds and incorporates external capacitor settings for NMI/reset power-up delay and watchdog frequency.

Feature Summary

• Dual-output architecture providing 200 mA and 50 mA currents for simultaneous microprocessor and peripheral power needs
• Integrated protection mechanisms including overload, short-circuit, and over-temperature safeguards
• Configurable reset circuitry with adjustable thresholds and double reset functionality for system reliability
• VDD tracking regulator capability allowing independent control via the VDD_EN pin

Applications

• Automotive microprocessor control units requiring robust power management under severe conditions
• Systems needing regulated voltage supplies with specific reset timing and watchdog requirements
• Electronic modules utilizing VDD tracking for synchronized power sequencing

Procurement Notes

Verify the specific suffix (e.g., TR) for packaging configuration as standard tubes may differ from reel options. Confirm AEC-Q100 qualification status for your specific automotive grade requirements. Check current lifecycle status as components may be marked NRND. Ensure compatibility with PowerSSO-12 footprint during PCB layout finalization.

Selection Notes

Select this component when dual rail generation is required from a single input source in automotive environments. Consider the 2% output voltage precision and wide operating temperature range (-40 °C to 150 °C) for harsh condition stability. Evaluate the need for adjustable reset thresholds and watchdog features before choosing over simpler fixed regulators.

Part Context

Part of the L9777 family of low-power voltage regulators. The series is engineered specifically for automotive electronics, offering enhanced protection features compared to standard industrial LDOs. The family shares similar architectural traits but varies in output current capabilities and package configurations to suit different system densities.

Replacement Considerations

Consult official substitution lists for equivalent dual-output automotive LDOs. Verify that any alternative matches the PowerSSO-12 package dimensions and pinout. Ensure replacement parts meet the same AEC-Q100 automotive qualification standards and thermal performance specifications.