Evaluation of LDMOS transistors for 10 Gbps switched mode applications and X-band power amplifier

In this article we report on the capability of integrated LDMOS transistors for power amplifiers in 10 gigabit per second (Gbps) communication systems, smart power systems and X-band power amplifiers. The switched mode properties of the amplifier were evaluated using a 10.3125 Gbps pseudo random bit error sequence (PRBS) signal. A test mask according to the IEEE P802.3aq 10GBASE-LRM Ethernet standard was applied to evaluate the recorded eye diagram. No single hit was detected in the forbidden test mask regions after measuring 6 million data points. Load-pull measurements at 11 GHz show an operational gain of 16 dB, a maximum power added efficiency (PAE) of 30 % and a maximum drain efficiency (EFF) of 38 %. RF small signal scattering parameters of the LDMOS transistor were measured up to 67 GHz. A cutoff frequency of 27 GHz and a maximum oscillation frequency of 61 GHz were extracted. The investigated n-LDMOS transistor is modularly integrated into a 0.25 μm SiGe:C BiCMOS Technology.