High Voltage RF LDMOS Technology for Broadcast Applications

LDMOS Technology for RF Power Amplifiers

“…A difference with standard CMOS is that an LDMOS transistor has a drain extension region to support the breakdown voltage. The 30-[1]- [4] and 50-V [10], [11] technology have a typical breakdown voltage of 70 and 120 V, respectively, which requires a drain extension length of 3 and 6 m. The epi thickness is about equal to the drain extension length. The LDMOS n source region is connected to the backside via a metal bridge, a p sinker, and a highly conducting p substrate.…”

“…The shields are laid out in a staircase design above the drain extension region. This staircase shield construction reduces the electric field peaks at the gate side of the drain extension, resulting in an almost ideal constant lateral field distribution [10].…”

“…The 50-V LDMOS was developed in 2007, to increase the power density and impedance levels, for broadcast and ISM applications [10], [11]. The efficiency power boundary contours for the 50-V LDMOS are plotted in Fig.…”

“…Lines guide the eye. Data taken from evaluation devices [7], [8], [10], [19]. V and equal to the supply voltage, measured at 1 MHz.…”

“…From low-frequency ( 500 MHz) and digital terrestrial television amplifiers applications, there has been a demand for high power levels. This has fueled the development of a 50-V supply voltage LDMOS [10], [11]. At the moment, the 30-and 50-V LDMOS technologies coexist on the market, each serving their own application segment.…”