STMicroelectronics SD2931-11

Overview

SD2931-11 from STMicroelectronics is a gold-metallized N-channel MOSFET RF power transistor in M174 epoxy-sealed package, designed for 50 V DC large-signal amplification up to 230 MHz. It delivers ≥150 W output power with 14 dB gain at 175 MHz, features 0.45 °C/W junction-to-case thermal resistance, and supports 10:1 load mismatch tolerance - deployed in industrial ISM band RF amplifiers requiring ruggedness and thermal stability.

For engineers reviewing the SD2931-11 datasheet, SD2931-11 pinout, SD2931-11 application, or SD2931-11 equivalent, key selection criteria include its 125 V V(BR)DSS rating, 200 °C max junction temperature, GFS/VGS sorting codes (e.g., Code A–R), thermally enhanced M174 package, and 175 MHz/30 MHz dual-band performance validation.

Technical Context

This device operates in common-source configuration with gate-controlled RF power switching. Its gold metallization ensures stable interconnect performance under high RF stress and thermal cycling, while the low Rth(j-c) of 0.45 °C/W enables sustained 150 W operation without derating below 80 °C case temperature.

The SD2931-11 is electrically identical to SD2931 but offers 25% lower thermal resistance via enhanced die attach and package design. It is characterized across 30 MHz and 175 MHz with full impedance data (ZIN = 1.2 – j2.0 Ω, ZDL = 2.0 + j2.4 Ω @ 175 MHz), supporting broadband matching networks for HF/VHF/UHF ISM transmitters.

Key Specifications

Pinout & Package

M174 epoxy-sealed hermetic package with 4-terminal flanged metal header; thermally optimized for direct heatsink mounting via screw hole (dimension F = 24.64–24.89 mm). Case acts as drain terminal; source terminals are internally bonded to both pins 2 and 4 for low-inductance return path.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar RF power MOSFET applications.

Compared with SD2931-11, SD2931 trades thermal performance for cost in single-device amplifiers, while MRF158 sacrifices output power and frequency range for higher voltage robustness - making SD2931-11 optimal for new 150 W ISM/UHF designs demanding thermal headroom and matching precision.

Availability

SD2931-11 is available at Aetrix Electronics and suitable for industrial RF heating, ISM band amplifiers, HF broadcast exciters, and amateur radio linear amplifiers requiring stable component supply across multi-year production cycles.

Supply support for SD2931-11 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, power, microcontroller, and RF components for industrial, automotive, and consumer markets.

The SD2931-11 belongs to ST's high-power RF MOSFET product line, engineered specifically for rugged, thermally demanding ISM band applications where reliability under continuous RF stress is non-negotiable.

FAQ

What is the maximum safe operating frequency for SD2931-11?

The SD2931-11 is characterized and rated for reliable operation up to 230 MHz, with full performance data provided at 30 MHz and 175 MHz. At 230 MHz, output power drops to ~120 W with 12 dB gain, and impedance matching becomes more sensitive - use only with verified broadband matching networks validated per Figure 2 and Table 7.

Can SD2931-11 be used in push-pull configuration?

Yes - its GFS and VGS sorting codes (A–R) enable precise bin-matching of two units for push-pull Class AB amplifiers. Matched pairs minimize even-order harmonics and improve IMD performance; ensure both devices share identical thermal mounting to avoid gain drift imbalance.

Is external gate protection required for SD2931-11?

Yes - although rated for ±20 V VGS, the gate oxide is susceptible to ESD damage. A series 10 Ω resistor and parallel 18 V Zener diode (or integrated ESD clamp IC) must be placed within 5 mm of the gate pin to limit transient voltage during hot insertion or RF coupling events.

What is the recommended heatsink interface for M174 package?

Use thermally conductive grease (e.g., Dow Corning TC-5123) or 0.1 mm silicone pad (e.g., Laird Tflex 400) between the M174 flange and heatsink. Mount with 20–25 in·lb torque on M3 screws; uneven pressure causes case warping and localized hot spots exceeding 200 °C junction limit.