STMicroelectronics SD2943W

Overview

SD2943W from STMicroelectronics is a gold-metallized N-channel RF power MOSFET in common-source configuration, rated for 50 V DC large-signal operation up to 150 MHz. It delivers minimum 350 W output power with 22 dB gain at 30 MHz, features 130 V drain-source breakdown voltage, 0.27 °C/W junction-to-case thermal resistance, and supports 3:1 VSWR load mismatch tolerance - used in industrial RF heating and ISM band amplifiers.

For engineers reviewing the SD2943W datasheet, SD2943W pinout, SD2943W application, or SD2943W equivalent, key selection criteria include its 450 W saturation power, low R_DS(on) of 2 V at 10 V_GS/20 A, thermal stability up to +200 °C junction temperature, and M177 thermally enhanced plastic package with flanged 4-lead layout.

Technical Context

The SD2943W operates in Class AB or Class C RF amplifier stages with fixed 50 V supply and 250 mA quiescent drain current. Its impedance data (Z_IN = 1.3 − j2.9 Ω at 30 MHz) enables broadband matching networks for HF/VHF/UHF bands up to 175 MHz.

Designed for rugged ISM applications, it integrates gold metallization for corrosion resistance and interconnect reliability, and uses a thermally optimized M177 package with direct case-to-heatsink interface - critical for maintaining <150 °C junction temperature under 450 W pulsed output conditions.

Key Specifications

Pinout & Package

The SD2943W is housed in the M177 (.550 DIA 4L NHERM WFLG) thermally enhanced plastic package with flanged 4-lead configuration. The metal flange provides direct mechanical and thermal attachment to heatsinks.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SD2933W and MRF158, the SD2943W uniquely combines 450 W saturation power, 0.27 °C/W thermal resistance, and gold metallization - making it optimal for thermally constrained, high-reliability ISM amplifiers demanding >10-year operational life.

Availability

SD2943W is available at Aetrix Electronics and suitable for industrial RF heating, ISM band amplifiers, HF broadcast transmitters, and UHF radar drivers requiring stable component supply across multi-year production cycles.

Supply support for SD2943W 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, designing and manufacturing analog, MCU, power, and RF devices for industrial, automotive, and consumer markets.

The SD2943W belongs to ST's high-power RF MOSFET product line, engineered specifically for rugged, high-efficiency amplification in unregulated ISM bands where thermal resilience and load mismatch tolerance are mission-critical.

FAQ

What is the maximum safe operating frequency for the SD2943W?

The SD2943W is characterized and specified for reliable operation up to 150 MHz, with full performance data provided at 30 MHz, 108 MHz, and 175 MHz. While usable beyond 150 MHz, gain and efficiency decline above this point due to parasitic capacitance limits; ST does not guarantee performance above 175 MHz.

Can the SD2943W be operated in Class D or E switching mode?

Yes - its 1100 mJ single-pulse avalanche energy rating and low R_DS(on) support robust Class D/E operation at 27.12 MHz and 40.68 MHz. However, gate drive must be optimized for fast transitions, and snubbing is required to manage V_DS overshoot during hard switching.

Is the flange electrically isolated from the drain in the M177 package?

No - the metal flange is internally connected to the drain terminal. Electrical isolation from the heatsink requires insulating hardware (e.g., mica washer + silicone grease) or use of an isolated mounting kit; improper isolation risks short-circuiting the RF output to chassis ground.

Does the SD2943W require external gate resistors for stability?

Yes - ST recommends a 10 Ω non-inductive gate resistor in series with the drive signal to dampen potential VHF oscillations. This is confirmed in the 30 MHz test circuit (Figure 13), where R1 and R3 serve as gate and source degeneration resistors to improve broadband stability.