Fabless semiconductor firm RFaxis Inc of Irvine, CA, USA, which designs RF semiconductors and embedded antenna solutions for wireless connectivity and cellular mobility, has developed an advanced envelope tracker to enhance the system-level efficiency of converged multi-mode multi-band (MMMB) power amplifiers, which are currently finding increasing popularity in smartphone designs.
The patent-pending RFaxis envelope tracker (RFeT) is a pure CMOS-based single-die envelope tracking modulator integrated into a family of converged MMMB power amplifiers (PA). It is engineered to support the latest class of cellular transceivers with envelope tracking algorithms and power management ICs (PMICs).
“As the cellular industry rapidly migrates from 3G to 4G/LTE networks to meet end-users’ insatiable demand for increased wireless data, the cost and efficiency of multi-mode multi-band PAs and associated RF front-ends are becoming major bottle necks,” says chairman & CEO Mike Neshat. “CMOS PAs and related technologies such as envelope tracking and antenna tuning hold the key to ultimate success of cost-effective 4G/LTE solutions,” he believes. “RFeT is a disruptive technology, as it eliminates the need for an external envelope tracking chip at the system level.”
The RFeT has digital control that is compatible with the MIPI (Mobile Industry Processor Interface) eTrak standard, and plays a critical role in enabling the RFaxis MMMB PA portfolio to achieve ultra-high efficiency (UHEFF) and high linearity while offering broadband, scalable support of GSM, GPRS, EDGE, WCDMA, HSPA+ and LTE, including other linear modulations such as CDMA, EVDO and TD-SCDMA, says the firm. This eliminates the need of using exotic envelope tracking power supplies (ETPS), where standard DC-DC converters or direct battery connection would suffice to achieve the targeted efficiencies.
