At the IMS 2014 in Tampa last week, Peregrine Semiconductors introduced its new line of UltraCMOS® Monolithic Phase & Amplitude Controllers (MPAC), the industry’s first monolithic RF solution to maximize Doherty amplifier performance. Through a digital interface, MPAC enables alignment of the phase and amplitude between the Doherty amplifier’s carrier and peaking paths. Designed for wireless infrastructure applications, MPAC improves system performance, lowers costs, increases reliability and provides maximum tuning flexibility.
The PE46120 is the first product of the MPAC family from Peregrine. It operates at a frequency range of 1.8 to 2.2 GHz. It has a wide positive and negative phase shift range and a fine step size, delivering a high linearity of 65 dBm IIP3 and extremely low power consumption of 300 µA. It provides performance advantages in power handling and port-to-port isolation. As MPAC is built on an UltraCMOS monolithic chip, RF engineers can rest assured with the most reliable and repeatable solution on the market. UltraCMOS technology enables superior ESD performance of 1 kV, an extended temperature range up to 105-degree Celsius and a wide power supply range from 2.7 to 5.5 V.
This product takes advantage of Peregrines Silicon on Sapphire, UltraCMOS process to deliver a monolithic solution. Freescale has a similar product which is based on GaAs, however they have used a module approach rather than a monolithic approach. Details on the Freescale part can be seen here - MMDS20254H.
Why MPAC?
While widely used in the wireless infrastructure industry, Doherty amplifiers require a considerable engineering investment to manually implement and optimize. Any mismatch or misalignment in phase and amplitude between the Doherty architecture’s carrier and peaking paths can quickly contribute to higher costs and degradation of the system’s overall performance. Even after optimizing with discrete components, the system remains inflexible to manufacturing variances from power amplifier assemblies.
MPAC solves this engineering challenge with the industry’s first monolithic solution to maximize asymmetric and symmetric Doherty amplifier performance. On an UltraCMOS chip, each MPAC product includes:
- 90-degree hybrid splitter
- Two phase shifters
- Two amplitude controllers
- Digital SPI interface
MPAC offers RF engineers improved system performance, lower costs, increased reliability and maximum tuning flexibility for either LDMOS (laterally diffused metal oxide semiconductor) or GaN (gallium nitride) based Doherty power amplifier architectures. The performance advantages include improvements in power added efficiency, linearity across the frequency range, Doherty bandwidth through better matching and effectiveness of the digital pre-distortion (DPD) loop. MPAC reduces bill of materials (BOM) costs by eliminating the need for external components such as DC blocking capacitors and reducing component count for greater board area. It also lowers costs by providing tighter production distributions on expensive power amplifier assemblies. With uniformity and repeatability between transceiver paths, MPAC increases system reliability and increases transceiver yield. Finally, MPAC delivers improved flexibility with adjustable phase and amplitude tuning for each independent path through the SPI digital interface. This flexibility enables real-time adjustments in order to optimize for operational or environmental changes.
The MPAC product family will eventually cover all cellular frequency bands. More products can be expected in the near future. A video about the product can be seen below:
