FAN5903BUCX

Special Purpose Regulators Overview

The FAN5903BUCX is a synchronous buck converter designed for power amplifiers in 3G/3.5G and 4G cellular infrastructure. It operates with an input voltage range of 2.7 V to 5.5 V and provides an adjustable output voltage from 400 mV to 3.5 V. The device delivers a maximum output current of 2.4 A with a switching frequency between 3 MHz and 6 MHz. It features a compact WLCSP-9 package, measuring approximately 1.34 mm by 1.29 mm with a height of 0.292 mm. The component functions within a temperature range of -40°C to +85°C.

Special Purpose Regulators Feature Summary

• Integrated bypass mode for high efficiency at light loads
• Synchronous rectification architecture for improved power conversion
• Compact wafer-level chip scale packaging for space-constrained designs

Special Purpose Regulators Applications

• Power supply for 3G/3.5G power amplifiers
• Power supply for 4G LTE power amplifiers
• Base station RF front-end modules

Special Purpose Regulators Procurement Notes

Verify the specific suffix 'B' indicates the integrated bypass mode variant distinct from standard versions. Confirm RoHS compliance status through official documentation. Check for obsolescence notices or last-time buy dates as Fairchild products may have transitioned statuses. Ensure the WLCSP-9 package availability matches your assembly capabilities.

Special Purpose Regulators Selection Notes

Select this component when a low-profile solution with bypass capability is required for cellular PA biasing. Compare the 2.4 A current limit against peak amplifier demands. Evaluate the 3-6 MHz switching frequency against EMI constraints. Verify that the 2.7 V minimum input voltage aligns with the system battery or rail specifications.

Special Purpose Regulators Part Context

This part belongs to the FAN5903 series of DC-DC converters. Fairchild Semiconductor was acquired by onsemi, leading to potential nomenclature changes where underscores are replaced by dashes. The FAN5903BUCX represents a specific functional variant within this family, distinguished by its bypass feature compared to other siblings like the FAN5903UCX.

Special Purpose Regulators Replacement Considerations

Check for updated onsemi part numbers replacing the Fairchild designation. Verify if the FAN5903UCX serves as a direct functional substitute if bypass mode is not required. Confirm pinout compatibility before substitution.