Since the 3SK41 is discontinued, you have three options:
Original equipment manufacturers (Hitachi, NEC) no longer host these files. However, you can find scanned, authentic copies at:
Pro Tip: When downloading, look for a document dated between 1985 and 1995. Later "generic" datasheets sometimes contain errors for this specific part.
The 3SK41 has been obsolete for decades. You will likely need a replacement. Based on direct electrical comparison, here are the best 3SK41 equivalents: 3sk41 datasheet
| Part Number | Compatibility Notes | Availability | | :--- | :--- | :--- | | BF981 | Nearly identical pinout (SOT-103). Superior noise figure (2dB). Drop-in with adapter. | Scarce | | BF998 | Surface mount (SOT-143). Higher transconductance. Requires a breakout board. | Common | | 3SK74 | Direct Japanese equivalent. Same TO-72 package. Perfect for vintage restorations. | Rare | | MPF121 | American equivalent, but higher capacitance. Not ideal above 150 MHz. | Obsolete | | Dual-gate 40673 | Metal can. Higher VDS tolerance but lower gain. Works as a slow substitute. | Obsolete |
Recommendation: For new designs, use the BF998R. For repairing a vintage 1980s TV tuner, search eBay or specialty surplus stores for NOS (New Old Stock) 3SK41B.
The 3SK41 was developed in the late 1970s and early 1980s by Japanese manufacturers like Hitachi, NEC, and Sanyo. It was famously used in the RF front-ends of high-end analog television tuners (Channels 1-12) and FM radio receivers. Since the 3SK41 is discontinued, you have three
Caution: MOSFETs are static-sensitive. Always wear a ground strap or touch a grounded metal surface before handling the 3SK41. Solder with a grounded iron.
In the world of RF (Radio Frequency) design, certain components achieve legendary status not because of flashy marketing, but due to pure performance and reliability. The 3SK41 is one such component. While it is now considered an obsolete or "end-of-life" (EOL) part, this N-channel dual-gate MOSFET remains highly sought after by vintage radio restorers, HF amplifier builders, and electronics hobbyists.
If you are searching for the 3SK41 datasheet, you are likely either repairing a classic tuner from the 1980s–1990s, designing a low-noise front-end for a receiver, or trying to cross-reference a replacement. This article serves as a detailed datasheet analysis, covering absolute maximum ratings, electrical characteristics, pin configurations, application circuits, and modern alternatives. Pro Tip : When downloading, look for a
Since an original datasheet is hard to find, use this quick in-circuit or out-of-circuit test procedure.
The classic application from the 3SK41 datasheet is a cascode-like RF amplifier. Unlike a single-gate MOSFET, Gate 2 acts as a shield and a gain control.