3sk41 Datasheet

The 3SK41 has been obsolete for decades. You will likely need a replacement. Based on direct electrical comparison, here are the best 3SK41 equivalents:

| 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. 3sk41 datasheet

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. Absolute maximum ratings

If replacing a 3SK41 (TO-72) with a BF998 (SOT-143):

Do not assume direct drop-in. Always verify bias voltages. DC characteristics (at specified test conditions)

       [ DC Power Bus (up to 400V) ]
                  |
                  |
             +----+----+
             |   D     |
             |         |
   [Gate]----| G   3SK |
   Driver    |         |
   IC        |   S     |
             +----+----+
                  |
                  +-----> [ Load (Motor/Lamp) ]
                  |
                 GND

(Note: A gate driver IC is essential to ensure the $V_GS$ threshold is met quickly to minimize switching losses in the linear region.)

Before designing any circuit, you must respect the limits listed below. Exceeding these values will destroy the MOSFET, as it is extremely static-sensitive.

| Parameter | Symbol | Rating | Unit | | :--- | :--- | :--- | :--- | | Drain-Source Voltage | VDS | 20 | V | | Gate 1 to Source Voltage | VG1S | ±15 | V | | Gate 2 to Source Voltage | VG2S | ±15 | V | | Drain Current | ID | 30 | mA | | Total Power Dissipation (Ta=25°C) | Ptot | 200 | mW | | Channel Temperature | Tch | 125 | °C | | Storage Temperature | Tstg | -40 to +125 | °C |

⚠️ Critical Warning: The input impedance of the 3SK41 is extremely high (in the megohm range). This makes it susceptible to damage from electrostatic discharge (ESD). Always use grounded soldering irons and anti-static wrist straps when handling.