Key Features

• Optimized IF selectivity for professional wireless receivers: helps suppress adjacent-channel blockers while maintaining usable passband flatness.
• Compact SM5050-8 footprint (5.0×5.0 mm) supports dense RF layouts and footprint reuse across the FSF-5050 family.
• Strong stopband attenuation to improve receiver immunity to out-of-band interferers in multi-transmitter environments.
• 50 Ω reference characterization with recommended external matching for predictable integration and repeatable VNA verification.

Key Specs

Test condition note: values are typically referenced to a 50 Ω measurement environment; external LC matching and PCB layout can shift insertion loss and ripple. Validate on your final board.

Family comparison

The FSF-5050-220M-221M6 family offers two key center frequencies, 220 MHz and 221.6 MHz. The table below summarizes typical passband width, insertion loss and stopband rejection so engineers can choose the right option according to system architecture and channel spacing.

※ Values shown are typical design targets. Actual performance depends on PCB layout, matching network and overall system design. Please allow sufficient margin and verify on the final hardware.

Detailed specifications (Ta = 25 °C unless noted)

Main electrical characteristics (summary)

Absolute maximum ratings (for the whole family)

※ Absolute maximum ratings are stress limits only. Prolonged operation at or beyond these conditions may result in performance degradation or reduced reliability. Always design with sufficient margin.

Applications (and why these specs matter)

Thanks to its compact package and selectivity, the FSF-5050-220M-221M6 family is well suited as an IF or narrow bandpass filter in VHF / UHF systems, including:

• Professional wireless microphone receivers — improves adjacent-channel immunity in dense stage environments; helps protect IF amplifiers and mixers from strong blockers.
• Narrowband wireless communications (telemetry / remote control) — supports tight channel spacing and reduces false triggering caused by nearby interferers.
• Security, alarm and access-control RF front ends — enhances receiver selectivity and can improve reliability under real-world RF congestion.
• Industrial wireless data acquisition — provides consistent IF filtering with a footprint that can be reused across multiple FSF-5050 frequency options.
• Other superheterodyne receivers with IF around 220 MHz — a practical drop-in IF selectivity element when a SAW solution is preferred over LC filtering.

In a superheterodyne architecture, placing these filters at the first or second IF stage improves dynamic range and adjacent-channel rejection and can relax requirements on subsequent demodulation and baseband circuitry.

Matching & integration guidance

Matching circuit and measurement conditions

• The family is designed for 50 Ω systems. We recommend using an LC matching network at both input and output ports.
• Start from the typical matching values provided in the datasheet (or reference design), then fine-tune L / C on the real PCB with a network analyzer to optimize insertion loss and return loss (S11 / S22).
• Follow the recommended grounding and fixture practices during measurement. Long RF cables or poorly designed adapters may add extra insertion loss and mask the true filter performance.

PCB layout and package considerations

• FSF-5050-220M-221M6 uses a 5.0×5.0 mm SM5050-8 package; design the land pattern according to the mechanical drawing.
• Keep traces around input and output pins as short and straight as possible, using controlled-impedance 50 Ω microstrip or coplanar waveguide structures.
• Provide a clean ground area around the SAW filter and avoid high-speed digital lines crossing the RF path to reduce coupling.
• Where necessary, partially opening the copper below the device can help to reduce mechanical stress on the package.

Reflow soldering and reliability

• Use a standard lead-free reflow profile: preheat around 150–180 °C, soak / reflow region around 220 °C and peak temperature up to approximately 245–260 °C.
• Limit the number of reflow cycles (typically no more than two) and verify the actual profile on your production line to avoid excessive thermal stress.
• For products requiring high-temperature / high-humidity or vibration / shock testing, validate with the SAW filter populated at an early project stage.

Ordering & options

Ordering code

Select the variant by IF center frequency and required passband width:

• FSF-5050-220M — 220 MHz center, narrower passband for tighter channel selection.
• FSF-5050-221M6 — 221.6 MHz center, wider (≈ 7–10 MHz) 3 dB bandwidth for broader IF requirements.

Selection path / upgrade options

If your IF plan changes (or you need a different bandwidth trade-off), keep the same 5.0×5.0 mm footprint and move within the FSF-5050 family:

Documents & downloads

Datasheets (PDF) are available below. If you need matching values, test fixtures, or integration support, contact us and specify your target part number.

Package outline (reference)

※ Use the official datasheet drawing for final land pattern dimensions and reflow guidance.

Related products

FSF-5050-220M-221M6 belongs to FCom Fuji Crystal's FSF-5050 SAW filter family. The series covers multiple IF frequencies so that the same PCB footprint can support different standards and bands.

• Common 5.0×5.0 mm SMD package across the FSF-5050 family simplifies layout reuse.
• Options available for narrow and wider passbands, fitting different modulation schemes and channel spacing.
• As part of a broader frequency-component portfolio, the FSF family supports end-to-end RF front-end design.

Additional frequency families (requested)

Further reading (selection & measurement)

Practical resources for selecting, measuring and integrating SAW filters into receiver IF chains:

FAQ