LFCN-400D+

Overview

The LFCN-400D+ is a low-pass ceramic filter manufactured by Mini-Circuits, designed for RF and microwave applications. It features a cutoff frequency of 400 MHz and operates with a nominal impedance of 50 Ohms. The device supports DC pass-through from input to output, providing a minimum isolation resistance to ground of 100 Mohms. Key electrical specifications include an insertion loss of 1 dB. The component is housed in a compact 4-SMD, No Lead surface-mount package, suitable for automated assembly processes.

Feature Summary

• LTCC construction provides high stopband rejection through strategic layout design
• Supports DC pass-through capability between input and output ports
• Surface mount packaging facilitates integration into modern electronic assemblies

Applications

• RF signal filtering in communication systems
• IF stage filtering in receiver architectures
• Harmonic suppression in transmitter outputs

Procurement Notes

Verify the specific suffix designation when ordering to ensure compatibility with DC requirements. The 'D' suffix indicates DC pass functionality, distinguishing it from standard variants that may require coupling capacitors if DC voltage is present at the ports. Confirm the package type matches the target PCB footprint. Consult the official datasheet for precise thermal and mechanical handling guidelines during installation.

Selection Notes

Select this component when a low-pass response up to 400 MHz is required alongside DC continuity. The 50 Ohm impedance rating ensures compatibility with standard RF transmission lines. Consider the surface-mount form factor for space-constrained designs. Evaluate the insertion loss specification against system noise budget requirements before finalizing the design.

Part Context

This part belongs to the LFCN series of LTCC low-pass filters produced by Mini-Circuits. The series offers various cutoff frequencies tailored for different RF bands. The LFCN-400D+ specifically targets applications requiring filtering below 400 MHz while maintaining DC connectivity, a feature not available in all variants of the family.

Replacement Considerations

Direct substitutes within the same family include the LFCN-400+ variant, which lacks DC pass capability and requires external coupling capacitors if DC isolation is needed. Ensure any replacement maintains the 4-SMD package dimensions and 50 Ohm impedance characteristics to preserve circuit integrity.