The **SFSKB4M30GF00-R1** (often referred to by the series SFSKB) is a high-performance **Ceramic Filter** manufactured by **Murata Electronics**. It is specifically designed for use in FM receiver circuits to provide intermediate frequency (IF) selectivity. --- ### 1. Technical Specifications Below are the primary electrical and mechanical characteristics of this component: | Parameter | Specification | | :--- | :--- | | **Center Frequency (fc)** | 4.30 MHz (Typical) | | **Bandwidth (3dB)** | ± 30 kHz min. | | **Insertion Loss** | 6.0 dB max. | | **Spurious Response** | 30 dB min. | | **Input/Output Impedance** | 1000 Ω | | **Mounting Type** | Surface Mount (SMD) | | **Operating Temperature** | -20°C to +80°C | --- ### 2. Core Functional Parts This component is a "Piezoelectric" device, meaning it relies on the mechanical vibration of ceramic material. Its internal structure consists of: 1. **Ceramic Element:** A lead zirconate titanate (PZT) ceramic substrate that acts as a resonator. It is physically shaped to vibrate only at specific frequencies (around 4.3 MHz). 2. **Electrodes:** Thin layers of silver or gold deposited on the ceramic surface to apply the electrical signal and pick up the filtered output. 3. **Base and Cap:** A heat-resistant resin or ceramic package that protects the internal vibrating element from humidity and mechanical shock while allowing for SMD soldering. 4. **Damping Material:** Internal support structures that prevent unwanted vibrations (harmonics) from interfering with the signal quality. --- ### 3. Application in Circuits The SFSKB4M30GF00-R1 is typically placed in the **Intermediate Frequency (IF) Stage** of a radio receiver. * **Selectivity:** Its primary job is to "select" the desired signal frequency while blocking neighboring noise and interference. * **Impedance Matching:** Because it has a 1000 Ω impedance, it often requires matching resistors or transformers when connected to low-impedance transistor stages. * **Miniaturization:** Its SMD form factor makes it ideal for compact consumer electronics like handheld scanners, automotive infotainment, and portable communication devices. --- ### 4. Part Number Breakdown * **SFSKB**: Product Series (Ceramic Filters for FM). * **4M30**: Center Frequency (4.30 MHz). * **GF**: Bandwidth and characteristics code. * **R1**: Packaging code (usually refers to Tape and Reel size).