Skip to main content

Glossary

Product Glossary

Description of Products

Polyfet RF Devices designs and manufactures VDMOS, LDMOS, and GaN RF power
transistors, and RF power amplifier modules. Learn more about our products here.

Sets of VDMOS transistors

VDMOS

VDMOS – Vertically Double Diffused Metal Oxide Semiconductor. Usable up to 1 GHz, 400 W, and across 12.5–50 VDC. Polyfet remains one of the few manufacturers still producing VDMOS transistors. We do so for a few reasons. One is to continue long-term support for our legacy customers. Another is because VDMOS technology remains competitive in performance for HF up to VHF applications. Lastly, to provide reliable replacement options for customers seeking VDMOS transistors that have been discontinued by other manufacturers. The bottom of the silicon chip is the Drain, requiring the package to contain the isolating material BeO, and source wires. The inductance of the source wires causes this series of products to have lower gain than others, making it a more stable device but requiring more stages for UHF applications.

Sets of LDMOS transistors

LDMOS

LDMOS – Laterally Diffused Metal Oxide Semiconductor. Usable up to 1.5 GHz, 2 kW, and across 5–50 VDC. The bottom of the silicon chip is the Source, which eliminates the need for the isolating material BeO in the package, or source wires. This results in the technology having 6–9 dB more gain than its VDMOS counterpart. Polyfet’s LDMOS transistors should be considered for narrowband applications up to 1.5 GHz or broadband applications up to 1 GHz.

Sets of GaN transistors

GaN

Gallium Nitride. Usable up to 3 GHz, 160 W, and across 24–48 VDC. The substrate material is SiC for high thermal conductivity. The bottom of the silicon chip is the Source, which eliminates the need for the isolating material BeO in the package, or source wires. Being a HEMT (High Electron Mobility Transistor), Polyfet’s GaN transistors should be considered for narrowband or broadband applications from 10 MHz up to 3.0 GHz. Typically, while higher priced per watt, a GaN transistor will provide ~10% higher efficiency in a broadband amplifier compared to an equally powered LDMOS transistor.

A amplifier module

Modules

Modules – Our RF amplifier modules were developed to fill the product gap in the market between a discrete transistor and a fully featured SSPA. Later models were developed per customers’ requests to package our evaluation amplifiers (TBs) in connectorized housings. Our amplifier modules are internally matched to 50-ohm input and output impedances and are usable up to 1260 MHz, 300 W, and across 12.5–50 VDC. External Vds and Vagc pins are provided for bias control. They contain Polyfet VDMOS, LDMOS, or GaN transistors suitable to the module specifications and application use.

Assembly

We manufacture our devices using a modular die concept. This helps reduce their thermal impedance and enables flexible production of devices tailored to our customers’ diverse power requirements.

Transistor Naming System

Product naming system table showing characters, meanings, and descriptions
Character Meaning Description
1st Technology S=VDMOS, L=LDMOS, G=GaN
2nd Package e.g. SP201 = AP Package
3rd Die Series e.g. SP201 = S2A Series Die
4th Supply Voltage 0=28V, 2=12.5V, 4=50V
5th Number of Dice e.g. SP201 has one die

Modules Naming System

Product naming system table showing characters, meanings, and descriptions
Character Meaning Description
1st Product Type M = Module
2nd Case Type A, B & C are 1” cube
3rd Min Freq A = 2 MHz C = 20 MHz D = 30 MHz
4th Max Freq Q = 512 Mhz R = 600 Mhz Z = 1GHz
5th Vdd 0 = 24-28 VDC 2 = 12.5 VDC 4 = 48 VDC
6th Series

Lot Code System

  • 2525-S is the lot code.
  • 2525 is the date code.
  • The first 25 represents the year 2025.
  • The second 25 represents the 25th week of the year.
  • S represents the specific lot for the 25th week of 2025. The letter also indicates the quantity of lots started for that week. That means the letter A is the first lot of the 25th week, B is the second, C is the third, and so on.

Therefore, lot code 2525-S is the 19th lot started in the 25th week of 2025.

Module lot code letters start with “M”.

Therefore, lot code 2525-MS is the 19th module lot started in the 25th week of 2025.

Our F series transistors are phased out. Their datasheets are available upon request. Please contact us to find a suitable replacement from our S series transistors.