L4949N

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

The L4949N is a fixed-output low dropout (LDO) voltage regulator manufactured by onsemi, providing a stable 5.0 V output with a maximum current capacity of 100 mA. It integrates a power-on reset circuit to ensure system reliability during startup and fault conditions. The device operates within an input voltage range of 6 V to 28 V, featuring a typical dropout voltage of 0.3 V and a maximum of 0.5 V at rated load. Packaged in an 8-pin plastic DIP (DIP-8), it is lead-free and RoHS compliant, designed for applications requiring precise voltage regulation and automatic reset functionality.

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

• Integrates a power-on reset generator to monitor supply voltage and assert a reset signal upon power-up or undervoltage events
• Provides a fixed 5.0 V regulated output with high line and load regulation capabilities
• Operates as a low dropout regulator, maintaining regulation with minimal input-to-output voltage differential
• Constructed with internal short-circuit current limiting and thermal shutdown protection mechanisms

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

• Microcontroller power supply systems requiring reliable startup sequencing
• Embedded logic circuits needing stable 5 V rail from higher voltage sources
• Industrial control modules utilizing power-on reset for safe initialization
• Battery-powered devices where low dropout performance extends operational life

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

Verify the specific suffix 'N' corresponds to the DIP-8 package configuration when sourcing. Confirm RoHS compliance status through official onsemi documentation for the exact part number variant. Ensure the application environment remains within the specified 6 V to 28 V input range to prevent damage. Check for any updated revision notes that may affect pinout or electrical characteristics compared to legacy Motorola datasheets.

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

Select this component when a fixed 5 V output with integrated reset functionality is required for 100 mA loads. It is suitable for designs where input voltages vary between 6 V and 28 V. Consider the DIP-8 package for through-hole mounting requirements. Evaluate if the standard reset timing meets system specifications, as no external delay components are supported in this basic configuration.

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

The L4949 series belongs to onsemi's family of multifunction low dropout voltage regulators. Originally developed by Motorola, these devices combine linear regulation with digital reset generation. The L4949N specifically denotes the non-adjustable 5 V version in a plastic dual in-line package. It serves as a foundational component for simple, cost-effective power management solutions in industrial and consumer electronics.

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

The NCV4949A is a verified automotive-grade replacement offering similar 100 mA output and reset features with enhanced sense capabilities. For general-purpose equivalents, consider the CS8101 which provides comparable 5 V/100 mA performance with reset and enable functions. Verify package compatibility and electrical parameter alignment before substitution.