RF Micro Devices Inc. announced on Monday the arrival of a line of various radio frequency products with envelope tracking (ET), which controls voltage to a power amplifier (PA) to make it run more efficiently.
The announcement was made at the Mobile World Congress in Barcelona, which runs through Feb. 28. RF Micro Devices introduced the RF7389, RF7390, RF7459, RF8081 and RF8085. These products consist of power management integrated circuits (PMIC), ET ultra-high efficiency PAs and ET multimode multi-band PAs.
Power management technologies, like ET, are critical as smartphones advance technologically. After the jump from 2G to 3G, smartphones used significantly more power and suffered shorter battery lives. With 4G, the RF PA eats a lot more power when putting out LTE signals, consuming 10 times the power of the same component in a 3G phone.
The term, 'LTE', itself may be a little vague. There are over 20 LTE bands globally. Supporting those bands and previous generations of bands consumes more power. It is not possible to have a truly global LTE phone because of the limitations making a mobile phone practical enough to support all the bands.
In an ET-less environment, supplying a constant voltage level wastes energy. The radio frequency (RF) signal is in a wave form with peaks and valleys in amplitude. At the low end of the wave, more voltage is supplied than necessary. The amount of wasted energy is even more severe with LTE since by its nature, the peaks are much higher than with 2G or 3G.
ET solves this problem. Instead of supplying a constant voltage level, ET causes the voltage level to adjust in sync with the amplitude of the RF signal.
LTE poses another problem that ET solves. Recently, it has been a common problem that LTE devices at the limits of a cell tower's range could receive signals from the tower, but the tower was unable to receive any signal from the device. The brute force solution would be to build more towers, but the regulations and requirements to add a tower exclude this from being a widespread option.
ET also solves this problem by allowing mobile devices to run at full power. As a result, both the tower and device can connect within range.
The explosion of mobile devices and data traffic has been difficult at best for vendors to keep up with. Technology does not exist in a vacuum as more advances introduce complexity and more problems. Power management solutions like the ET products offered by RF Micro Devices will be needed for LTE to gain wider use.
Edited by Brooke Neuman