The **2SC3356-R25** (often marked simply as **R25**) is a high-frequency NPN silicon epitaxial transistor designed specifically for low-noise amplification in the VHF, UHF, and CATV bands. --- ### 1. General Specifications The 2SC3356 is part of the "Microwave Low Noise" family, typically housed in a small surface-mount package (SOT-23). | Parameter | Specification | | :--- | :--- | | **Polarity** | NPN | | **Collector-Emitter Voltage ($V_{CEO}$)** | 12 V | | **Collector Current ($I_C$)** | 100 mA | | **Total Power Dissipation ($P_{tot}$)** | 200 mW | | **Transition Frequency ($f_T$)** | 7.0 GHz (Typical) | | **Noise Figure ($NF$)** | 1.1 dB @ 1.0 GHz | | **Package Type** | SOT-23 (3-pin) | --- ### 2. Key Characteristics * **High Gain:** It offers high power gain (typically 11.5 dB at 1.0 GHz), making it efficient for weak signal amplification. * **Low Noise:** The primary selling point is its low noise figure, which ensures minimal interference is added to the signal during amplification. * **R25 Marking:** The "R25" is the specific **device marking code** printed on the physical component to identify it, as the full part number is too long for the SOT-23 package. * **$h_{FE}$ Classification:** The 2SC3356 comes in different gain grades. The "R25" code usually corresponds to a specific DC current gain ($h_{FE}$) range, typically between **50 and 300** depending on the specific manufacturer's binning (e.g., NEC/Renesas). --- ### 3. Pinout Configuration (SOT-23) When looking at the top of the device (pins pointing down): | Pin Number | Name | Function | | :--- | :--- | :--- | | **1** | **Base** | Input trigger for the transistor | | **2** | **Emitter** | Ground/Common (usually) | | **3** | **Collector** | Output/Power supply connection | --- ### 4. Common Applications Due to its high-frequency capabilities, the 2SC3356-R25 is commonly found in: 1. **LNB (Low Noise Block) Converters:** For satellite television reception. 2. **RF Front-ends:** In wireless communication devices (pagers, handheld radios). 3. **Oscillators:** High-frequency local oscillators in tuners. 4. **Signal Boosters:** Antenna pre-amplifiers for TV and Radio. ---