FSF-5050-433M~435M 433MHz IF SAW Filter Series

Product Overview: 433–435 MHz 5×5 mm IF SAW Filter Family

The FSF-5050-433M~435M series is a 5.0×5.0 mm IF SAW filter family from FCom Fuji Crystal, optimized for the 433 MHz ISM band. All devices share the same 5.0×5.0 mm SMD package to simplify platform-based designs and PCB layout reuse. Within the series you will find an 8 MHz wideband 433 MHz SAW filter, narrowband high-impedance 433.42 MHz and 433.92 MHz IF SAW filters, and a wideband 435 MHz version, allowing designers to cover remote control, data transfer and high-selectivity receiver applications with one common footprint.

The 433 MHz wideband filters are well-suited to multi-standard or multi-channel systems with a relatively wide distribution of frequencies, while the 433.42 MHz / 433.92 MHz narrowband devices achieve 3 dB bandwidths of a few hundred kilohertz with well controlled group delay. This improves channel separation and image rejection in a congested ISM band. The 435 MHz version provides a wide IF passband across roughly 430–440 MHz, making it ideal when the system IF plan is shifted higher, or when multiple nearby IF frequencies must be supported in a single receiver chain.

Frequency and topology at a glance: FSF-5050-433M (433 MHz, 50 Ω single-ended, ~8 MHz passband), FSF-5050-433M42 (433.42 MHz narrowband, high-impedance), FSF-5050-433M92 (433.92 MHz narrowband, high-impedance, including high-temperature/high-impedance version), FSF-5050-435M (435 MHz, 50 Ω single-ended, wide IF passband).

Target Systems & Typical IF Placement

This family is commonly used in 433 MHz ISM receiver chains where selectivity and blocker rejection are required without increasing PCB area. Typical placements include (1) high-IF stages in superheterodyne receivers, where a higher intermediate frequency is selected to relax image constraints, and (2) IF/RF filtering blocks in compact industrial modules where repeatable production performance is needed.

Target systems: ISM remote control receivers, telemetry and sensor gateways, building automation nodes, industrial RF front ends, and channelized narrowband receivers.
Why SAW here: a stable passband and steep skirts help preserve receiver sensitivity under strong adjacent or far-out interferers.

Key Features

Unified 5.0×5.0 mm SMD package and pinout for 433 MHz platform-type RF/IF modules.
Multiple center frequencies at 433, 433.42, 433.92 and 435 MHz, covering both wideband and narrowband IF applications.
Includes 50 Ω single-ended ports and several-hundred-ohm high-impedance ports for use with single-ended or differential IF amplifiers.
433 MHz and 435 MHz wideband versions maintain low insertion loss over 8–10 MHz passbands, ideal for general-purpose remote-control and multi-channel systems.
433.42 / 433.92 MHz narrowband versions provide 3 dB bandwidth on the order of several hundred kilohertz, enabling tight channel selection and adjacent-channel rejection.
High stopband attenuation at image and far-out frequencies enhances receiver dynamic range and immunity to strong interferers.
RoHS compliant, lead-free construction, compatible with standard reflow soldering profiles.

Typical Applications

433 MHz ISM remote control systems, automotive keyless entry, garage door openers and access control.
Industrial and building automation telemetry, wireless sensors and smart metering.
IF filtering for 433 MHz data transceivers and wireless communication modules.
Channelized narrowband receivers, RF test and communication simulators.
Complete timing and RF front ends using FCom crystals, TCXO / VCXO and OCXO devices together with FSF SAW filters, from antenna front end to precision clock.

Key Specs (Quick Summary)

Quick-reference summary for selection and system planning. Typical values at 25°C; verify test conditions and limits in the official datasheets.

Package5.0×5.0 mm SMD

Frequencies433 / 433.42 / 433.92 / 435 MHz

Port options50 Ω or high-impedance narrowband

TemperatureUp to −40°C to +85°C (by option)

Electrical Characteristics Overview: FSF-5050-433M / 433M42 / 433M92 / 435M

The table below summarizes representative electrical parameters of the FSF-5050-433M~435M IF SAW filter family for quick comparison and device selection. For detailed design work, FCom recommends using the latest S-parameter and characterization data to fine-tune matching networks and group delay behavior.

FCom Part No.	Center Frequency Fc (MHz)	Port Type & Impedance	Passband / Bandwidth (Typical)	Insertion Loss (Typ / Max, dB)	Max Input Power (dBm)	Recommended Operating Temp (°C)
FSF-5050-433M-B	433	50 Ω single-ended input / output	Approx. Fc ±4 MHz wide passband, tuned for wide-temperature, low-power applications	Typ ~2.7 / Max ≤4.5	–	−20 ~ +70
FSF-5050-433M42	433.42	High-impedance input/output (~227 Ω // 3.3 pF)	3 dB bandwidth around 680 kHz, targeting 433.42 MHz narrowband telemetry/remote-control channels	Typ ~2.2 / Max ~4.0	10	−40 ~ +85
FSF-5050-433M92	433.92	High-impedance input/output (~227 Ω // 3.3 pF)	3 dB bandwidth ~670–720 kHz, optimized for typical 433.92 MHz remote-control channels with good passband flatness	Typ ~2.2 / Max ~4.0	10	–
FSF-5050-433M92-HT	433.92	High-impedance input/output (~768 Ω // 2.7 pF)	3 dB bandwidth approx. 0.5–0.95 MHz, balancing narrow channel selectivity with extended temperature conditions and compatibility with specific IF amplifiers	Typ ~3.0 / Max ~4.0	10	−40 ~ +85
FSF-5050-435M	435	50 Ω single-ended input / output	Approx. 430–440 MHz wide IF passband, for higher IF plans around 433–435 MHz or multi-frequency integration	Typ ~2.3 / Max ≤3.3	10	−40 ~ +85

Note: The values above are representative typical data for device comparison and front-end planning only. Guaranteed production specifications and test conditions are defined in FCom Fuji Crystal’s official product documentation and the latest S-parameter files.

Matching / Impedance Notes & Selection Guidance

By providing multiple center frequencies and impedance options in the same 5×5 mm platform, the FSF-5050-433M~435M series lets RF engineers switch between wideband and narrowband IF architectures – and between single-ended and high-impedance ports – without changing package or PCB footprint.

433/435 MHz 50 Ω single-ended versions: FSF-5050-433M and FSF-5050-435M can be treated as 50 Ω single-ended SAW filters, placed directly between the mixer and IF amplifier. In many cases, only minor LC trimming is required to optimize VSWR and group delay.
433.42 / 433.92 MHz narrowband high-impedance versions: FSF-5050-433M42 and FSF-5050-433M92 present several-hundred-ohm impedances in parallel with a small capacitance, making them suitable for high-impedance IF amplifiers or transformer-coupled networks. To connect them to 50 Ω environments, classic series-inductor plus shunt-capacitor matching networks can be used. Start from the equivalent impedance in the datasheet, simulate IL and group delay, then fine-tune with VNA measurements.
Wide temperature and power considerations: For operation over −40°C to +85°C and beyond, prioritize wide-temp versions such as FSF-5050-433M, 433M42, 433M92 and 435M. In real circuits, include input limiting and ESD protection so transient pulses do not exceed the filter’s rated RF power.
PCB layout recommendations: For all FSF-5050 filters, use short, straight RF traces with a solid ground plane. Avoid excessive test points and protection components close to the RF pins to minimize parasitic capacitance/inductance that could distort the passband or group delay.

Further reading (selection + implementation): How to Choose the Optimal SAW Filter for Your System · SAW Filter PCB Layout & ESD Design · Professional Wireless Receiver Engineering Guide.

Ordering Code / Options

Select the part number by center frequency and port environment (50 Ω or high-impedance narrowband), then confirm the operating temperature requirement. For channelized systems, narrowband versions typically provide stronger adjacent-channel suppression, while wideband versions are simpler to integrate across multi-channel plans.

433 MHz wideband (50 Ω): FSF-5050-433M-B
433.42 MHz narrowband (high impedance): FSF-5050-433M42
433.92 MHz narrowband (high impedance): FSF-5050-433M92 / FSF-5050-433M92-HT
435 MHz wideband (50 Ω): FSF-5050-435M

Selection Path / Upgrade Options: If your IF plan shifts or you need neighboring passbands, consider adjacent FSF-5050 families: FSF-5050-420M~427M8, FSF-5050-440M~446M, FSF-5050-458M5, FSF-5050-460M~465M. For the full family entry, visit SAW Filters (FSF Families).

Documents & Downloads

Download the official datasheets for detailed test conditions, matching references, and production limits. If you need S-parameters, evaluation support, or a customized option, submit an RFQ with your target IF plan and impedance environment.

Datasheets

FSF-5050-433M (433MHz) SAW Bandpass Filter Datasheet (PDF) FSF-5050-433M92 (433.92MHz) SAW Bandpass Filter Datasheet (PDF) FSF-5050-435M (435MHz) SAW Bandpass Filter Datasheet (PDF)

Tip: For best correlation to your board, validate matching and insertion loss using VNA fixtures consistent with your impedance environment (50 Ω vs high-impedance).

Package Drawing

5.0×5.0 mm outline drawing for footprint planning and mechanical integration.

Frequently Asked Questions (FAQ)

Q1: In a 433 MHz ISM remote-control system, should I use the 433 MHz wideband filters or the 433.42 / 433.92 MHz narrowband versions?

A: If your system only needs coarse frequency separation or must support several nearby channels, the wideband FSF-5050-433M or FSF-5050-435M is usually easier to design and less sensitive to data rate and modulation. When you need strict channel spacing, better adjacent-channel and image rejection in a congested 433 MHz ISM band, the narrowband FSF-5050-433M42 or FSF-5050-433M92 provides narrower 3 dB bandwidth and more controlled group delay – at the cost of tighter matching and IF planning.

Q2: How can I connect a high-impedance narrowband SAW filter to a 50 Ω RF front end or test equipment?

A: High-impedance IF SAW filters can be matched to 50 Ω using simple LC or L-/π-type networks. A common method is to place small series inductors on the input and output and adjust shunt capacitors to ground until both return loss and passband shape are acceptable. In practice, start with the equivalent impedance from the datasheet, build a circuit model in your RF simulator, and then validate and fine-tune with S-parameter measurements on a vector network analyzer to maximize receiver sensitivity and selectivity.

Q3: Are FSF-5050-433M~435M filters suitable for long-term outdoor or industrial operation?

A: Most devices in this family (including FSF-5050-433M, 433M42, 433M92 and 435M) support typical operating ranges around −40°C to +85°C. With proper PCB layout, shielding and ESD/power limiting, they are suitable for the majority of outdoor and industrial applications. For more extreme temperature, RF power or ESD conditions, please contact the FCom engineering team to determine whether additional protection, shielding or thermal management is required.

Q4: What is the MOQ and lead time for the FSF-5050-433M~435M series?

A: MOQ and lead time depend on the exact part number (frequency, impedance version, temperature grade) and production schedule. Send your target PN and quantity via RFQ/Contact and we will confirm the latest MOQ, standard lead time, and any expedite options.

Q5: Can I get samples and evaluation support (matching, layout, S-parameters)?

A: Yes. Samples are available for qualification, and FCom can provide design guidance including typical matching networks, layout recommendations, and measurement notes. Contact us with your IF plan, impedance environment, and bandwidth requirements.

Q6: Do you support customization (center frequency, bandwidth, impedance, package)?

A: Custom options are possible depending on performance targets and volume. Typical customization topics include center frequency alignment, passband shaping, impedance targets, and application-specific validation.

Q7: Why is there no public price listed on the product page?

A: Pricing is project-based and varies with part number, quantity, packaging, and delivery terms. Please submit an RFQ for an official quotation.

Samples & Technical Support
For FSF-5050-433M~435M samples, English datasheets, or design assistance on 433 MHz IF filter chains, please contact us via Contact Us or Online Inquiry. Our engineering team can help you integrate SAW filters and timing devices into a complete RF/IF and clocking solution.

ISO certifications: ISO9001 · ISO14001

FSF-5050-433M~435M IF SAW Filter Series