3sk41 Datasheet Jun 2026

: 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.

The 3SK41 is a depletion‑mode, N‑Channel dual‑gate MOSFET. Unlike a standard MOSFET, it features two electrically independent gate terminals (Gate1 and Gate2) that provide greater flexibility in circuit design, especially for gain control and mixer stages. The four leads (Source, Drain, Gate1, Gate2) are housed in a compact hermetically sealed , a standard for high‑reliability RF transistors of its era.

: The vintage metal CAN4 package isn't just for aesthetics; it provides excellent thermal protection and minimizes electrical interference. Why It’s a "Cult Classic"

The 3SK41 remains a powerful, reliable choice for high-frequency RF amplification in legacy or specialized equipment. Its ability to provide low-noise amplification, combined with easy AGC control via its dual-gate design, makes it a noteworthy component in the history of communication electronics. When repairing or designing older RF circuits, the 3SK41 (or its modern equivalents) is an excellent component to consider. 3sk41 datasheet

A highly popular, widely available Silicon dual-gate MOSFET from NXP/Infineon. While it has different biasing characteristics because it is silicon-based rather than Gallium Arsenide, it serves a very similar functional purpose in VHF/UHF amplifier and mixer stages.

): Crucial for stability, this value is exceptionally low (around 0.02 pF to 0.03 pF). This minimal feedback capacitance is what allows the 3SK41 to amplify UHF signals stably without self-oscillating. 5. How the Dual-Gate Structure Works in Circuit Design

Gallium Arsenide (GaAs) for superior electron mobility. Configuration: Dual-Gate N-Channel depletion mode. Primary Focus: Low noise figure and high power gain. : The input impedance of the 3SK41 is

The 3SK41 acts as an efficient, low-distortion mixer. The incoming RF signal is fed to Gate 1, while the Local Oscillator (LO) signal is fed to Gate 2. The nonlinear mixing action inside the channel produces the desired Intermediate Frequency (IF) at the drain output. This method provides excellent isolation between the RF and LO ports. 6. Tips for Circuit Design and Handling

In the , the leads are arranged in a circle around the metal can. A small tab or a flattened area on the can indicates the Source lead. The Drain is typically the single lead that protrudes on the opposite side of the package. The two gate leads are located on the sides. It is strongly recommended to consult the original service manual for the specific equipment or a reliable datasheet when identifying the leads on an actual device.

When used as a frequency mixer, the RF signal is injected into , and the Local Oscillator (LO) signal is injected into Gate 2 . The non-linear mixing action happens cleanly inside the channel. Because Gate 1 and Gate 2 are physically isolated, this design severely reduces LO radiation back out through the antenna terminal, a common issue in single-gate mixer designs. 6. Sourcing and Modern Alternatives : The vintage metal CAN4 package isn't just

| Equivalent / Replacement | Type / Package | Key Considerations & Guidance | | :--- | :--- | :--- | | | N-Channel Dual-Gate MOSFET | Common TV tuner ICs; pinout differs, may require board modification; BF998 offers superior noise figure | | 3N201, 3N211 | N-Channel Dual-Gate MOSFET | Popular, common replacements in vintage gear; verify pinout and adapt if necessary | | 3SK40, 3SK45, 3SK48 | N-Channel Dual-Gate MOSFET | Near-identical specs; some tuner servicing guides report success with direct substitution of 3SK48 for 3SK41 | | NTE454 | N-Channel Dual-Gate MOSFET | Modern universal replacement; widely available, but confirm pin compatibility before use | | KP382A (Russian) | N-Channel Dual-Gate MOSFET | Potential replacement from Russian electronics; verify pin configuration matches your circuit |

Minimizes feedback, reducing the risk of unwanted oscillations without complex neutralizing circuits. 2. Pinout and Physical Package

It is currently considered an obsolete or "hard-to-find" part but can still be sourced through specialty electronic distributors like Jotrin Electronics

These values indicate the stresses that the device can withstand without permanent failure. Operating at or near these limits for an extended period is not recommended.