SD4931

Overview

The SD4931 is an N-channel MOS field-effect RF power transistor designed for 50 V DC large-signal applications up to 250 MHz. It delivers a minimum output power (POUT) of 150 W with a gain of 14.8 dB at 175 MHz. The device features improved ruggedness with a drain-source breakdown voltage (V(BR)DSS) exceeding 200 V and excellent thermal stability. It supports a 20:1 all-phase load mismatch capability, ensuring reliable operation under varying impedance conditions.

Feature Summary

• High-power RF amplification in HF/VHF/UHF bands
• Robust performance under severe load mismatch conditions
• Enhanced thermal stability for continuous operation

Applications

• HF/VHF/UHF RF power amplification
• 50 V DC large-signal transmitter stages
• Industrial, Scientific, and Medical (ISM) equipment

Procurement Notes

Verify the specific package type and marking code against the official STMicroelectronics datasheet before procurement. Ensure that the supplier provides traceability documentation confirming the component's authenticity and compliance with the 2002/95/EC European directive regarding restricted substances. Cross-reference the part number suffixes to confirm exact electrical binning and packaging specifications.

Selection Notes

Select the SD4931 when designing circuits requiring 150 W output power at frequencies up to 250 MHz with a 50 V supply. Consider its high breakdown voltage (>200 V) for enhanced ruggedness against voltage spikes. Evaluate the thermal management requirements due to its power density, ensuring adequate heat sinking to maintain the specified thermal stability and prevent junction temperature exceedance during continuous wave operation.

Part Context

The SD4931 belongs to STMicroelectronics' family of high-frequency power transistors utilizing sealed-ceramic and ST Air Cavity package technologies. These packages are engineered to efficiently transfer thermal energy from the die, thereby increasing reliability and reducing servicing costs compared to traditional packaging methods. This design philosophy extends to other models like the SD4933 and STAC series, focusing on high signal power production at high frequencies.

Replacement Considerations

For direct functional replacement within similar 50 V, 150 W RF amplifier designs, consider the SD4933 if higher power (300 W) and lower frequency (up to 100 MHz) applications are acceptable. Verify pin compatibility and thermal interface dimensions before substitution. No other identical 150 W 50 V parts are explicitly listed as direct substitutes in the provided data.