STMicroelectronics SD3931-10

Overview

SD3931-10 from STMicroelectronics is an N-channel MOSFET RF power transistor in common-source configuration, rated for 100 V DC large-signal operation up to 150 MHz. It delivers ≥175 W output power with ≥23 dB gain and 50–57% drain efficiency at 150 MHz, housed in the M174 hermetic ceramic package with flange. It is designed for HF/VHF/UHF broadband amplifier stages in industrial RF heating and broadcast transmitters.

For engineers reviewing the SD3931-10 datasheet, SD3931-10 pinout, SD3931-10 application, or SD3931-10 equivalent, key selection criteria include its 250 V V(BR)DSS rating, 0.45 °C/W junction-to-case thermal resistance, 175 W P1dB capability at 150 MHz, and gate threshold voltage sorting (1.5–4.0 V), critical for bias stability in high-power linear amplifiers.

Technical Context

The SD3931-10 operates as a single-ended, common-source RF power amplifier stage with fixed 100 V drain supply and 250 mA quiescent drain current. Its dynamic performance is characterized at 150 MHz with matched 50 Ω source and load impedances, where ZIN = 0.42 − j3.1 Ω and ZDL = 3.4 + j5.5 Ω define the required matching network topology.

Thermal management is central to reliability: the device features a low RthJC of 0.45 °C/W and a maximum junction temperature of 200 °C, enabling stable operation under sustained 175 W output with proper heatsinking. Its gate drive requires ±20 V tolerance and exhibits low input capacitance (CISS = 500 pF) for efficient broadband matching.

Key Specifications

Pinout & Package

The SD3931-10 is housed in the M174 hermetically sealed ceramic package with metal flange for thermal and RF grounding. Dimensions are 25.53–26.67 mm (L) × 12.57–12.83 mm (G) × 5.56–5.584 mm (A), with 4 leads arranged in a single-row configuration.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MRF171G and BLF177, the SD3931-10 offers superior thermal performance and guaranteed 175 W output at 150 MHz in a hermetic package-making it optimal for mission-critical HF/VHF amplifiers where reliability, efficiency, and long-term parameter stability are non-negotiable.

Availability

SD3931-10 is available at Aetrix Electronics and suitable for RF heating systems, broadcast transmitters, amateur radio amplifiers, and HF communications repeaters requiring stable component supply across extended production lifecycles.

Supply support for SD3931-10 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, digital, and mixed-signal ICs for industrial, automotive, and power applications.

The SD3931-10 belongs to ST's high-power RF transistor product line, engineered specifically for rugged, high-efficiency HF/VHF/UHF amplifier stages in industrial and broadcast infrastructure where thermal resilience and parameter consistency are essential.

FAQ

What is the recommended gate bias voltage for linear operation at 150 MHz?

The SD3931-10 achieves optimal linearity and efficiency at IDQ = 250 mA, corresponding to a gate-source voltage of 1.5–4.0 V depending on the specific unit's VGS(Q) sort code (e.g., 'DD' = 1.5–1.6 V, 'H' = 2.5–2.6 V). Bias networks must accommodate this range using temperature-compensated resistive dividers or active current sources to maintain stable quiescent current across thermal cycling.

Can SD3931-10 be used in push-pull configuration?

No-the SD3931-10 is a single-die, common-source N-channel MOSFET with two source terminals (Pins 2 and 4) intended for enhanced thermal and RF grounding, not complementary pairing. Push-pull operation requires matched N- and P-channel devices or dual-die symmetric packages, neither of which apply here. It is specified only for single-ended amplifier topologies.

What is the maximum safe operating area (SOA) limitation at 100 V drain supply?

At VDS = 100 V, the absolute maximum continuous drain current is 10 A (per Table 2), but practical SOA is constrained by thermal limits: with RthJC = 0.45 °C/W and TJ(max) = 200 °C, case temperature must remain ≤75 °C to sustain 175 W output. Pulse operation beyond DC ratings requires adherence to the SOA curve in Figure 6, respecting both voltage-current and thermal time constants.

Is the M174 package lead-free and RoHS-compliant?

Yes-the SD3931-10 is offered in ECOPACK®-compliant M174 packaging, meeting the 2002/95/EC RoHS directive and subsequent EU environmental regulations. The device uses lead-free terminations and halogen-free molding compounds, with full compliance documentation available via ST's quality portal under ECOPACK grade "ECOPACK2".