Over a decade ago as a replacement for LDMOS transistors launched two transistors - bipolar (bipola

LDMOS transistors have selected element for microwave applications. An overview is given of the technological improvements in the 3.6 GHz LDMOS - Run Over the past decade, and are shown in RF performance of LDMOS microwave products for radar in S.
Over a decade ago as a replacement for LDMOS transistors launched two transistors - bipolar (bipolar) for RF power applications [1,2]. Today technology true food kitchen phoenix is the technology LDMOS RF power leads for base station true food kitchen phoenix applications, especially for applications true food kitchen phoenix in GSM-EDGE 1 and 2 giga - Run applications, WCDMA 2.2 GHz - Run Recently WiMax applications around 2.7 GHz - and 3.8 Giga Hertz - Hz.
One last niche application areas used two devices true food kitchen phoenix - polar domain was 3-4 GHz microwave - Run, such as S-band radar main reason for this was that earlier generations of LDMOS presented at 3 GHz - run similar performance true food kitchen phoenix compared to the co - polar , redesign of complex radar systems true food kitchen phoenix do not seem justified.
Main lever of LDMOS is compatible application - scale, enabling continuous improvement of LDMOS technology [3,4], and he made the appearance of the latest generation of LDMOS performance exceeding two - polar frequency domain S, together with some additional benefits such as stiffness true food kitchen phoenix and behavior better thermal. In this article an overview is given on the improvements in the 3-4 GHz LDMOS - Run and display performance microwave products.
LDMOS transistors true food kitchen phoenix are controlled devices - voltage so that current is flowing gate (gate) as two devices - polar. This allows voltage control circuit voltage (bias) simpler and cheaper compared two devices - polar. The disadvantage of the oxide - a weak exchange no longer exists, since a ESD devices are standard.
Another advantage is the connection source (source) to the rear platform of the LDMOS, at Slhtknim bi - polar has Collector (collector) on the back. Therefore two devices - Polar utilize a BeO isolated, together with the wire link. LDMOS allow replacing BeO toxic on - by ceramic or plastic enclosures are environmentally friendly. This is a huge benefit of the LDMOS. Picture true food kitchen phoenix of Ceramic SOT502 packages is shown in Figure 1. Internal adjustment of input and output true food kitchen phoenix is included in the package to transform the impedance levels and reduce the RF losses. Source substrate fusion welded to the chassis without the need for seedlings link to the source. Without true food kitchen phoenix Wires source LDMOS no additional source inductance and high gain LDMOS power transistor.
LDMOS even better thermal stability than the bi - polar. Two devices - polar positive temperature coefficient cause thermal runaway. Bi - polar should therefore elaborate temperature compensation such as load resistors (ballast) to protect the device against failures. High current, LDMOS negative temperature coefficient automatically turning off the device when it is fully powered. This creates a natural true food kitchen phoenix advantage in regard to thermal properties and toughness.
RF performance of LDMOS frequencies of 3-4 GHz - Run improved dramatically over the past decade to become significantly better performance compared to two - polar. Chapter IV presented the RF performance of LDMOS for 3.6 GHz - run, but before the first date technology of the LDMOS is described in Chapter III.
LDMOS technology from NXP's manufacturing true food kitchen phoenix plant processed CMOS 8-inch lithography capable of producing true food kitchen phoenix up to 0.14 mm, where the process LDMOS due process CMOS C075 (USD mm0.35). Additions to the C075 process are LOCOS isolation, a piece of source to the substrate, metallization (metallization) the back, adding CoSi2 gate silicon, tungsten shield structure of the estuary (drain) with 5 AlCu metallization layers.
A schematic cross section of the LDMOS is shown in Figure 2. N + source region of the LDMOS is connected to the rear via a metal bridge, a piece (sinker) p + and p + substrate (substrate) has a very high conductivity. Source to drain current will flow if the gate is positively biased inverting the well the p-diffused sidebar.
In addition to the LDMOS including expanding area of the estuary to create true food kitchen phoenix tension judgment of more than 65 volts, and metallization multi - layered the estuary to provide excellent electrical roaming features. Shielded outfall gate using a tungsten extremely low feedback capacitance and reliability features delivered hot (hot carrier) good. Many fingers are placed in parallel to create a piece (die) Power, forming a total finger length of 10-100 mm.
Show LDMOS devices tested at 3.6 GHz - Run with the structure of attracting - load (load-pull) cooled test circuit - water. Device power level of 10-20 watts to enable a low Q matching with load pull tuners and measurement of development of the device itself. All devices supply voltage true food kitchen phoenix stress of 28 V and a drain current of 5 ms - amp finance finger length to get class AB performance.
Development of power density (3dB compression power) is shown in Figure 3. Over the past decade the power density almost doubled to reach over 1W/mm for the seventh generation of NXP's LDMOS. Especially for microwave applications have a constant demand for higher power. The gain at 3.6 Giga - Hertz is shown in Figure 4. Praise be increased from 7dB in 2000 to 14 dB recent technology generation. Two devices true food kitchen phoenix - polar gain of about 9 dB, similar to the first performance of LDMOS generations, do not justify redesign of complex radar systems. However, praise the 14 dB of later generations 5dB in excess dialog technology - disorder, and justifies the LDMOS technology planning.
As part of Figure 4 plotted the reduction true food kitchen phoenix of gate length subsequent generations. The gate length was reduced dramatically to increase the praise transistor using conductivity increasing interaction (transconductance). Now other contributions, such as input capacitance, feedback capacitance and inductance source becomes important. LDMOS leverages the advantage of low source inductance by connecting the rear source (unlike the bond wires two devices - polar) and low feedback capacitance due to the shielding structure.
Development of drain efficiency at 3.6 GHz - Run is illustrated in Figure 5. The peak efficiency of the latest generations of LDMOS is about 55%, while the theoretical maximum efficiency type AB is 78.5%. The theoretical efficiency