Amplifiers, whether as RF gain blocks, as low-noise amplifiers (LNAs), or power amplifiers (PAs), are essential building blocks in microwave systems. Over the last decade, a growing number of RF integrated circuit (RFIC) amplifiers have become available in place of larger and more expensive discrete designs. While these RFIC products can't always match the pure performance of a discretedevice amplifier, RFICs provide the convenience of small size and, often, ease of installation in a system.
Many RFIC amplifiers are available in chip form or supplied in drop-in or surface-mount packages, providing users with several mounting options. For example, the model TGA1342-SCC from TriQuint Semiconductor is an automatic-gaincontrol (AGC) amplifier based on GaAs MESFET technology. It operates from 2 to 20 GHz and consists of nine fieldeffect transistors with typical midband noise figure of 3.5 dB and nominal gain of 9 dB on a chip measuring 3.4 x 2.0 x 0.1 mm. The IC amplifier draws 60 mA current from a +5 to +8 VDC supply and delivers +17.5 dBm output power at 1-dB compression.
In comparison, the same company offers the model TGA2507-SM threestage driver amplifier for 11 to 17 GHz, housed in a surface-mount package measuring 4.0 x 4.0 x 0.9 mm. Based on GaAs pseudomorphic high electron mobility transistor (HEMT) technology, the Ku-band RFIC amplifier delivers 25-dB small-signal gain with +17-dBm output power at 1-dB compression.
In terms of bandwidth, the model SDA-6000 from RF Micro Devices is a GaAs PHEMT amplifier with DC to 50 GHz bandwidth. It provides 8.5 dB typical gain with 4.3 dB typical noise figure with +14-dBm output power at 1-dB compression at mid-band frequencies. The midband noise figure is 4.3 dB.
At lower frequencies, the model ABA-31563 from Avago Technologies is a silicon bipolar RFIC gain block amplifier supplied in a plastic SOT-363 surface-mount package for use from DC to 3.5 GHz. It provides nominal gain of 21.9 dB at 2 GHz with output power of +2 dBm.
Another InGaP HBT RFIC amplifier, the model AP3013 from RFIC Technology Corp., with a frequency range of 1.9 to 2.7 GHz, is ideal for WiMAX and other wireless communications applications. It is designed for use with a single +3.3-VDC supply and provides 34 dB power gain with +24 dBm output power at less than 3-percent error-vector-magnitude (EVM) performance.
The SKY65038-70LF is an LNA from Skyworks Solutions suitable for use from 0.5 to 6.0 GHz. Based on GaAs PHEMT technology, it offers15 dB gain and 2 dB noise figure at 1 GHz from a +5-VDC supply. It is supplied in a 4-pin SOT-89 plastic package.
The ERA-1+ RFIC amplifier from Mini-Circuits is a DC-to-8-GHz amplifier supplied in a drop-in, plastic micro-X package. Based on InGaP HBT technology, it is unconditionally stable and internally matched to 50 Ohms. It yields 11.8 dB typical gain at 2 GHz with 4.3 dB typical noise figure and +12 dBm typical output power at 1-dB compression.
The CMM1100-QF LNA from Mimix Broadband operates from 2 to 18 GHz in a 4 x 4 mm QFN surface-mount package. It delivers 15 dB small signal gain and 3.8 dB noise figure across most of its operating band, with +15 dBm output power at 1-dB compression. It is designed for 100 mA at +5 VDC.
This is just a sampling of narrowband and broadband RFIC amplifiers available in both chip and packaged forms based on a variety of different high-frequency transistor technologies. For more on the technologies, see the "RF Primer."