3sk41 Datasheet ◆

The 3SK41 is a legacy N-channel dual-gate MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) primarily designed for VHF (Very High Frequency) applications. These components were staples in the design of high-sensitivity radio equipment, particularly as amplifiers and mixers. Because this part is largely discontinued or considered "vintage," finding modern documentation requires looking back at classic semiconductor standards. 🚀 Technical Specifications Overview

Veswin: Contains detailed information on pinouts, circuit diagrams, and equivalent components. 3sk41 datasheet

NTE161: A universal replacement part often found in repair catalogs. ⚠️ Usage Considerations The 3SK41 is a legacy N-channel dual-gate MOSFET

Key specs to focus on for design and what they imply

VDS (often low, e.g., ~20 V): device intended for low‑voltage circuits; don’t use in higher supply rails without level shifting or protection.
VGS(max) (often ±7–10 V): gate oxide is fragile — gate surge protection and proper bias resistors are needed.
ID and RDS(on): small currents and relatively high RDS(on) mean the part is not for power switching but for low‑power RF amplification/mixing.
gm and ft: higher gm → higher small‑signal gain; ft indicates usable frequency range. Compare gm and ft to target RF band.
Gate and inter‑electrode capacitances (Cgs, Cgd, Cds): set the device’s loading on preceding stages and influence matching network values; large Crss can cause feedback and instability at high frequencies.
Dual gates: the second gate provides control (gain/VFO mixing) or shielding — datasheet shows transfer ratios for Gate1 and Gate2 and coupling between them.