The **SFSKA4M50CF00-R1** is a surface-mount (SMD) ceramic filter manufactured by **Murata Electronics**. It is specifically designed for use in Intermediate Frequency (IF) stages of communication equipment. ### 1. Technical Specifications The following table summarizes the key electrical and physical characteristics of the component: | Parameter | Specification | | :--- | :--- | | **Center Frequency (fc)** | 4.5 MHz | | **Bandwidth (at 3dB)** | ±60 kHz min. | | **Insertion Loss** | 6.0 dB max. | | **Stop Band Attenuation** | 20 dB min. (at fc ± 400kHz) | | **Input/Output Impedance** | 1000 $\Omega$ | | **Mounting Type** | Surface Mount (SMD) | | **Operating Temperature** | -20°C to +80°C | --- ### 2. Core Functional Role This part acts as a **Band-pass Filter**. Its primary job is to allow signals within a specific range around 4.5 MHz to pass through while significantly suppressing (attenuating) signals outside that range. * **Ceramic Piezoelectric Technology:** It utilizes the mechanical vibration of piezoelectric ceramics to achieve high selectivity and stability. * **Application Focus:** It is commonly found in the FM sound demodulation circuits of televisions, VCRs, and FM receivers where a 4.5 MHz IF is standard. --- ### 3. Physical Footprint and PCB Integration The SFSKA series features a compact, low-profile design suitable for automated assembly. * **Package Style:** Small-form factor SMD. * **Termination:** Lead-free soldering compatible. * **Circuit Integration:** Because it has a specific impedance (1000 $\Omega$), it often requires impedance matching resistors or transformers when interfacing with low-impedance amplifiers to prevent signal reflection and distortion. --- ### 4. Typical Circuit Diagram Logic In a standard application, the filter is placed between the Mixer stage and the Limiter/Amplifier stage: ```text [ Mixer Out ] ---> [ Impedance Matching ] ---> [ SFSKA4M50CF00-R1 ] ---> [ IF Amplifier ] ```