At the 2012 IEEE MTT-S International Microwave Symposium(IMS)in Montreal,Canada(17–22 June),Freescale Semiconductor of Austin,TX,USA,which provides RF power technology for cellular markets,has launched new Airfast transistors engineered to boost the efficiency,peak power and signal bandwidth of next-generation base stations.The firm says that,with the new offerings,its flagship Airfast RF power product line now includes at least one solution for each cellular band and supports both small-and large-cell base-station deployments.
The cost-effective,small-configuration Airfast RF power solutions are designed to help network equipment manufacturers and operators support multiple wireless standards,manage escalating data transmission rates,and keep capital and operating costs low.
The Airfast devices are made using LDMOS silicon technology.But,to complement them,Freescale is also announcing a new class of highly integrated gallium arsenide(GaAs)MMIC control circuits called advanced Doherty alignment modules(ADAM)that enables real-time digital adjustment of phase and amplitude for the optimization of traditional Doherty power amplifiers.The modules are designed to work with Airfast devices to boost overall system performance,including increased power efficiency,output power and linearity across the frequency band.
Specifically,the MMDS25254H ADAM is a GaAs monolithic microwave integrated circuit(MMIC)based on E-pHEMT and InGaP HBT technology(and housed in an RoHS-compliant industry-standard QFN 6mm x6mm package)that allows phase and peaking adjustments from 2300 to 2800MHz.The device has a constant 90 degree phase offset between port 2 and port 3 versus frequency(500MHz bandwidth).Field adjustment is possible to optimize power amplifier performance under different conditions(power level,supply voltage,temperature).Product families for 700-1000MHz and 1800-2200MHz are also in development.
The AFT18HW355S is an in-package Doherty device for high-power PCS-and DCS-band applications.Delivering 56dBm of peak power in a single device with efficiency exceeding 48%at average power of 8dB OBO,it offers performance that rivals more expensive GaN-based solutions,it is claimed.Capable of operating at either 1805-1880MHz or 1930-1995MHz,the compact device uses Freescale's enhanced video bandwidth technology to enable full-band,multi-carrier operation.
The AFT09S282N is a 900MHz,28V LDMOS device that offers RF performance at 720-960MHz and delivers what is claimed to bethe highest peak power in OMNI plastic over-molded packaging on the market(490W load pull peak power).
The AFT18S230S is a 1.8GHz,28V RF power LDMOS transistor that delivers a symmetric Doherty efficiency of 45%and 17dB of gain at 8dB OBO(a level of efficiency typically achieved by more complex and expensive solutions employing asymmetric-only Doherty techniques;when used in asymmetric Doherty PAs,the device can deliver even higher-efficiency performance).
The AFT21S230S is a 2.1GHz 28V device delivering high efficiency for a 230W-rated RF power LDMOS transistor.Housed in NI-780S-6 packaging for VBW up to 100MHz,it is designed for use in either symmetric or asymmetric Doherty applications.In symmetric deployment it is engineered to deliver 45%efficiency at 8dB OBO and 15.5dB of gain.
