Dapu Microelectronics RF Filters and Components

Dapu offers several types of RF filters for different applications. SAW (Surface Acoustic Wave) filters provide excellent selectivity for cellular and GPS applications from 400MHz to 2.7GHz. BAW (Bulk Acoustic Wave) filters offer higher Q and better performance for challenging interference environments. Ceramic filters are cost-effective solutions for ISM band and consumer applications. LC filters provide broadband performance for general-purpose filtering. Dapu also offers duplexers and multiplexers for FDD systems. Each filter type has different characteristics in terms of insertion loss, rejection, size, and cost. The choice depends on your specific frequency, performance, and cost requirements.

Select SAW for cellular, BAW for high performance, ceramic for cost-sensitive applications.

Insertion loss is the signal power loss through the filter, measured in dB. Lower insertion loss means more signal passes through the filter. Typical insertion loss ranges from 1-3dB for good filters, though narrowband filters may have higher loss. High insertion loss reduces receiver sensitivity and transmitter output power. In receive paths, every dB of insertion loss directly degrades system sensitivity. In transmit paths, higher insertion loss requires more PA power, reducing battery life. When selecting filters, balance insertion loss against other parameters like rejection and bandwidth. Dapu filters are optimized for low insertion loss while maintaining good rejection characteristics.

Select filters with <2dB insertion loss for receive paths, <3dB for transmit paths.

SAW (Surface Acoustic Wave) filters use acoustic waves traveling along the surface of a piezoelectric substrate. They are cost-effective and work well up to about 2.7GHz. BAW (Bulk Acoustic Wave) filters use waves traveling through the bulk material, enabling higher Q factors and better performance at higher frequencies (up to 6GHz+). BAW filters have steeper roll-off, better temperature stability, and smaller size but cost more. For cellular and GPS applications below 2.7GHz, SAW filters are typically sufficient. For 5G high bands (3-6GHz) or applications requiring superior selectivity, BAW filters are preferred. Dapu primarily offers SAW filters for cost-sensitive applications.

Use SAW for cellular/GPS below 2.7GHz. Use BAW for 5G high bands or premium performance requirements.

Most Dapu RF filters are internally matched to 50Ω and don't require external matching components. Connect the filter using 50Ω transmission lines (microstrip, stripline, or coplanar waveguide). Keep traces short to minimize insertion loss and parasitic effects. Use ground vias near the filter ground connections. Avoid sharp bends in traces near the filter. The filter should be placed close to the antenna or LNA for receive paths, and close to the PA for transmit paths. For filters requiring external matching, the datasheet will provide the matching network schematic. Always follow the recommended PCB layout in the datasheet for best performance.

Use 50Ω transmission lines. Keep traces short. Follow datasheet layout recommendations.

Dapu RF filters typically have ESD ratings of 1-2kV HBM (Human Body Model) and 250-500V CDM (Charged Device Model). While this provides reasonable protection, standard ESD precautions should always be followed during handling and assembly. The SAW filter structure is sensitive to ESD damage which can degrade performance or cause failure. Use grounded workstations, ESD-safe tools, and proper personnel grounding when handling RF filters. Store components in ESD-safe packaging until ready for use. For high-ESD environments, consider adding external ESD protection devices. Contact us for specific ESD ratings for your filter part numbers.

Standard ESD precautions required. 1-2kV HBM typical rating.