FAN1951D18X

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

The FAN1951D18X is a fixed-output low-dropout linear regulator manufactured by onsemi, providing a stable 1.8V output with a minimum guaranteed current of 1.5A. It utilizes a PNP pass element to achieve a maximum dropout voltage of 500mV at full load. The device incorporates overcurrent limiting and thermal shutdown for protection. Key functional features include an external logic-level enable pin and an open-collector error flag output that signals undervoltage or over-current conditions.

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

• Integrates an external enable input for logic-controlled power management
• Provides an active-low error flag output to indicate fault conditions
• Utilizes a PNP pass element for high-efficiency low-voltage regulation
• Includes built-in overcurrent limiting and thermal shutdown mechanisms

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

• Low-voltage CPU, DSP, and FPGA power conversion
• Post-regulation for switching mode power supplies
• Cable and satellite set-top box power distribution
• PCI graphics adapter card voltage regulation

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

Verify the specific suffix 'X' indicates tape and reel packaging as documented in the ordering information. Confirm the manufacturer origin, noting historical Fairchild Semiconductor data may now be managed under onsemi. Ensure the fixed 1.8V output specification matches the design requirements before procurement.

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

Select this component when a fixed 1.8V rail is required with up to 1.5A continuous load capability. The inclusion of an enable pin and error flag makes it suitable for systems requiring precise power sequencing and fault monitoring. Verify that the input voltage remains within the recommended operating range to maintain stability and regulation accuracy.

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

This part belongs to the FAN1950/FAN1951 family of 1.5A low-dropout regulators. While the FAN1950 lacks control pins, the FAN1951 variant adds an enable input and error flag for enhanced system integration. Both share identical electrical performance characteristics regarding dropout voltage and current handling capabilities.

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

Direct substitutes include the FAN1951D25X for applications requiring a 2.5V output instead of 1.8V. Other options within the same package and current rating should be evaluated based on specific voltage requirements and feature sets.

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

What is the function of the FLAG pin?

The FLAG pin is an open-collector output that goes active-low to indicate an undervoltage or over-current condition.

How does the FAN1951 differ from the FAN1950?

The FAN1951 includes an additional Enable (EN) pin and an Error Flag (FLAG) pin, whereas the FAN1950 operates continuously without these control features.