Michael Louis Frank

FBAR Rx filters for handset front-end modules with wafer-level packaging

We present results of balanced Rx filters based on thin-film bulk acoustic resonator (FBAR) technology for GSM handset front-end module applications. The balanced filtering is achieved by using a lattice filter topology. The filter is hermetically sealed using wafer-level packaging with solder bumps on each terminal, ready for flip-chip assembly. The size of the filter is less than 1 mm/spl and/2 and the height is less than 0.35 mm. The typical broadband rejection is better than 35 dB, and in-band insertion loss is less than 2 dB. The small size and good temperature stability make FBAR filters an ideal choice for front-end module applications.

A 1.7 mA low noise amplifier with integrated bypass switch for wireless 0.05-6 GHz portable applications

An ultra low current low noise amplifier with an integrated bypass switch has been developed using PHEMT technology. The LNA/Sw uses only 1.7 mA when powered and less than 1 A when bypassed. It is usable from 50 MHz to 6 GHz. This enables portable systems such as Bluetooth, Home RF, PDAs, wireless LANs. The LNA provides 15 dB gain, 1.8 dB noise figure with 50 /spl Omega/ load at the output and /spl Gamma/opt at the input. Bypass mode provides 5 dB insertion loss into the same I/O match. The LNA and bypass switch with associated control circuitry are integrated into a single RFIC and housed in the miniature SOT package. This LNA/Sw provides lower current and easier usage with comparable NF, gain, and bandwidth than previously reported products.

A miniature PHEMT switched-LNA for 800 MHz to 8.0 GHz handset applications

A powerful monolithic integrated switched-LNA utilizing advanced pseudomorphic GaAs has been developed. The Swt-LNA covers 800 MHz to 8000 MHz but the primary application focus is 800 MHz to 2500 MHz. In gain mode the Swt-LNA operates on a single 3V supply and the current (thus output IP3) can be adjusted from 5 to 60 mA (input IP3=+1 to +15 dBm). The Swt-LNA provides a typical 1.4 dB noise figure and 14 dB gain. When the current control pin sets the LNA to 0 mA, the Swt-LNA goes automatically into bypass mode. Bypass mode has typically 2 dB loss and +35 dBm IIP3. The IC is packaged in a low cost 2 mm sq. SOT-343 plastic package. This Swt-LNA provides smaller size, lower NF, wider bandwidth, and easier usage than previously reported, similar products.

12F-3 A Pitch-Catch UHF Piezoelectric Transformer Fabricated with Thin Film PZT Transducers

A novel high isolation piezoelectric transformer operating in the UHF band is presented. The acoustically coupled transformer (ACT) is composed of thin film PZT transducers on both sides of an insulating substrate. The input transducer launches an acoustic wave through the insulating substrate to the output transducer in a pitch/catch mode to realize a 1:1 turns ratio. Appropriate series connection of multiple input transducers and parallel connection of the corresponding output transducers results in a transformer with an N:1 turns ratio. The ACT is fabricated using standard thin film and wafer scale fabrication techniques on a 150 mm diameter alumina wafer. The PZT transducers are deposited on Pt electrodes on both sides of the substrate by a sol-gel method. A backside photo-aligner is used to assure alignment of front and back side devices. Thousands of transformers can be made at once, thus eliminating costly one-off manufacturing. A novel differential electrode structure is used to apply the electric field to the PZT transducers without the need to etch the PZT film to reach the bottom electrode. Scattering (S) parameters of the ACT devices were obtained experimentally with a novel double-sided probe station that used air co-planar microprobes and a differential network analyzer. ACT transformers of 1:1 voltage ratio, with high DC isolation, and operating in the 20 to 200 MHz range are realized. The transformers exhibit a series of low insertion loss resonant peaks, spaced ~12 MHz apart, with |S21| as low as -1.2 dB when conjugate matched at the input and output ports. A temperature coefficient of frequency of -49 ppm/degC is measured. Power densities in excess of 400 Watts/cm3 are achieved. Dispersion diagrams for the allowed vibration modes are presented.