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GaN vs LDMOS: Technology Comparison

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This page dives into the differences between GaN (Gallium Nitride) and LDMOS (Laterally Diffused MOSFET) technologies. Let’s explore their characteristics and applications.

ParameterGaNLDMOS
Full formGallium NitrideLaterally Diffused MOSFET
Applications• GaN on SiC (50V) provides high efficiency, power density and higher gain in smaller package • Used for broadband applications due to higher output impedance and lower Cds capacitance • Advantages: GaN transistors have small parasitic capacitance and hence they have easy wideband matching compare to LDMOS transistors of identical power level.• LDMOS is used for cellular and broadcast narrowband applications due to high power and efficiency • LDMOS(50V) is used for <1.5 GHz applications while LDMOS (28V) is used for frequencies upto 4 GHz • Disadvantages: LDMOS transistor has large Cgs/Cds capacitance due to large peripheral in its design. This will limit the bandwidth.
Fmax (GHz)30 GHz for GaN (50V)22 GHz for LDMOS (28V) 15 GHz for LDMOS (50V)
Power Density (W/mm)5-10 for GaN (50V)0.8 for LDMOS (28V) 2 for LDMOS (50V)
Efficiency at P 1dB (%)70 for GaN (50V)60 for LDMOS (28V) <55 for LDMOS (50V)
Bandwidth (MHz)500-2500 for GaN (50V)100-400 for LDMOS (28V) 100-500 for LDMOS (50V)
Cds (pF/ W)1/4 smaller for GaN (50V)0.23 for LDMOS (28V) 1/2 smaller for LDMOS (50V)
Cgs (pF/ W)1/2 smaller for GaN (50V)0.94 for LDMOS (28V) 1/2 smaller for LDMOS (50V)

Key Takeaways

  • GaN: Excels in broadband applications requiring high efficiency and power density. Its smaller parasitic capacitance makes wideband matching easier. GaN is known to offer more power and performance.
  • LDMOS: Well-suited for narrowband applications like cellular and broadcast, where high power and efficiency are crucial. LDMOS comes in at a lower price point, making it appealing for a wide range of applications. Its higher capacitance can limit bandwidth.