STMicroelectronics SD2942 — HF/VHF/UHF RF Power MOSFET Transistor

STM · N-Channel RF Power MOSFET · 50 V · ~200 W · 1PC · RFQ within 24h

The STMicroelectronics SD2942 is an N-channel RF power MOSFET in the legacy M-244 / SOT-262 ceramic-flange package, designed for high-power common-source push-pull and Class AB / Class C linear amplification from HF through UHF. At 50 V V_DS, the part is typically specified for 200 W of RF output at 30 MHz, 150 W at 100 MHz, and 100 W at 175 MHz — a familiar workhorse in 100–200 W amateur, broadcast, and industrial RF amplifier designs. KOEED lists the SD2942 as a related semiconductor category alongside our core Allen-Bradley, Siemens, Mitsubishi, Omron, Fanuc, Schneider, Yaskawa, Panasonic, and KEYENCE automation lines, because the same plant-floor engineering teams that spec PLC CPUs also maintain the RF heating, plasma, and broadcast subsystems the SD2942 drives.

1. Key Technical Specifications / Overview

The SD2942 is built on a gold-metallized ceramic flange with gold or aluminium bond wires, bolt-down to an external heat sink, and biased from a +50 V rail. The published headline figures — 200 W at 30 MHz, 150 W at 100 MHz, 100 W at 175 MHz — describe typical push-pull common-source operation; production broadcast and amateur users typically de-rate to a 150 W class for long key-down reliability. The table below summarises the parameters KOEED keeps on file for RFQ purposes.

2. Application Scenarios / Where It Fits

The SD2942 sits in an adjacent category to the PLC, servo, and HMI inventory that anchors our core nine-brand matrix. It is the kind of part an experienced automation engineer specs when an RF subsystem inside a process line needs repair or upgrade. The most common placements are:

• Industrial RF heating — plastic welding, wood-glue curing, induction-assisted drying, and pre-heating stations on extrusion or converting lines that sit alongside the line PLC.
• Plasma generation — RF plasma sources for semiconductor etch, surface treatment, and thin-film deposition tools where the SD2942 is the final RF amplifier stage driving the matching network.
• Amateur HF/VHF amplifiers — 100 W / 150 W / 200 W linear amplifier builds for the 80 m – 2 m bands; matched pairs of SD2942 in push-pull are a familiar reference design.
• Broadcast transmitters — VHF low-band and FM broadcast final stages, including legacy 1.5 kW – 5 kW amplifier chains that use multiple SD2942 devices in parallel.
• MRI RF amplifiers — replacement RF power stage in low-to-mid field MRI systems, where the 50 V rail and ceramic flange suit medical chassis constraints.
• RF lighting and industrial ISM-band transmitters — plasma lamps, dielectric heaters, and 27 / 40 MHz industrial / scientific sources.

The same factory teams that standardise on Allen-Bradley ControlLogix for the line PLC, Siemens SIMATIC for the safety controller, and Mitsubishi MR-J4 servo for the motion axis, will reach for the SD2942 when a plasma or RF heating cell goes down and a 50 V RF power stage has to be replaced without redesigning the cabinet. That is the gap KOEED is set up to fill.

3. Integration & Wiring Notes

The SD2942 is an unmatched device, so every connection on the RF path is part of the design. Pinning follows the standard M-244 / SOT-262 layout: Gate 1, Gate 2, Drain 1, Drain 2, with the flange serving as the source and thermal ground. Plan your layout around the following practical points.

• Push-pull pairing: Two devices are mounted mirror-symmetric on the same heat sink, with gate drives fed from a 1:1 gate transformer and drains combined in a broadband transmission-line balun. Matched sets are available on RFQ.
• Gate bias: Use a regulated +5 V gate-bias rail with a low-noise op-amp or dedicated bias generator; the SD2942 only needs a few hundred mA of quiescent current at idle. Avoid routing the bias trace across the drain pad.
• Drain feed: The +50 V rail should be RF-decoupled at the device with a low-ESR electrolytic plus a high-Q ceramic (typically 1 nF to 100 nF stack), and the feed choke should be self-resonant well above the operating frequency.
• Source grounding: Source returns through the flange; keep the source-lead length short by using a low-inductance copper strap or direct bolt-down to a ground plane, not long leads.
• Matching network: Because the device is unmatched, build the input and output networks as discrete L-C cells on Teflon or low-loss ceramic substrate, not FR-4.
• Thermal sensor: Mount a thermocouple or NTC directly on the flange, roughly 5 mm from the device body, and feed it to the cabinet interlock; the SD2942 is not thermally protected internally.
• Cabinet integration: Wire the safety chain to the same PLC platform already in the line — typical pairings in our projects are Omron SYSMAC or Schneider Modicon safety relays handling the RF interlock and over-temperature trip.

4. Installation & Commissioning Tips

A few field-tested practices will save a lot of bench time on a 50 V RF stage.

• Heat sink preparation: Lap the heat sink with 400-grit paper, clean with isopropyl alcohol, and apply a thin, even layer of high-quality thermal compound. Mounting torque matters — typically 0.6 N·m on M3 screws, tightened in a star pattern, to keep the flange flat.
• First power-up without RF: Apply gate bias first, then bring the +50 V rail up slowly through a current-limited bench supply. A healthy SD2942 at idle will draw the published I_DQ (typically 100–250 mA per side) with no oscillation.
• Static check: Before applying RF drive, verify drain current with zero input — any drift or oscillation indicates a layout or bias problem, not a bad part.
• Drive level: Bring the RF input up in 5 dB steps, watching drain current and output on a dummy load. The SD2942 will draw 10–15 A peak at 200 W output; if it pulls significantly more, the matching network needs re-tuning.
• Burn-in: Run at 70% of rated output for one hour, then re-torque the flange screws after cool-down to remove any thermal-creep slack.
• Spare philosophy: Plant engineers who keep a matched pair on the shelf for hot-swap recovery typically standardise on the same part family; KOEED supports that with paired sets and we can also cross-reference the SD2942 to the SD2931 / SD2941 / SD2943 family when you are building a multi-band amplifier.
• Documentation: Log the bias, drive, and output numbers on commissioning; KOEED archives these in our real-time records feed so the next RFQ on the same platform has a known-good baseline.

5. Procurement, Warranty & Lead Time

The SD2942 is sourced as a related/adjacent category at KOEED, sitting next to our PLC and servo inventory. Because STM and the broker market for this device are volatile, every quote is a fresh check, not a static price. The workflow below is what we run on every RFQ.

• RFQ turnaround: Send your quantity, target date, and any matching requirement to Moritta@KOEED.COM; you will get availability and price within 24 hours on business days.
• Authenticity: Parts are procured through vetted channels and visually inspected for date code, lot, and package integrity. Counterfeit gold-flange SD2931 / SD2942 parts are an industry-known problem; we will not ship a part we cannot trace.
• Warranty: Standard 12-month limited warranty against manufacturing defect, in line with the rest of the KOEED automation line — see the return policy for RMA procedure.
• Lead time: In-stock singles ship within 2 business days after payment clears; matched pairs and large quantity orders typically 2–4 weeks, depending on the broker market at quote time.
• Worldwide shipping: DHL / FedEx / UPS door-to-door, with the shipping policy covering incoterms and export documentation.
• BOM-level quotation: If the SD2942 is part of a larger cabinet or RF heating line that also needs PLC, servo, or HMI parts, send the full list — we can quote Allen-Bradley, Siemens, Mitsubishi, Omron, Fanuc, Schneider, Yaskawa, Panasonic, and KEYENCE parts on the same BOM through the Create a Quote form.

Not sure whether the SD2942 is the right part, or you are looking at a cross-reference to a Siemens RF amplifier module, a Fanuc spindle drive replacement, or a Mitsubishi MR-J servo on the same line? Drop the line drawing or BOM into an email to Moritta@KOEED.COM and our engineering desk will come back with availability, datasheet links, and a suggested cross-reference within one business day.

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