To improve battery life, Texas Instruments has introduced a new envelope tracking power supply device that supports 3G and 4G LTE multi-mode, multi-band RF power amplifiers used in smartphones and tablets.
The new LM3290 step-down converter with integrated DC boost and companion LM3291 linear amplifier support the use of envelope tracking techniques in RF transmitters. This helps to reduce the power amplifier temperature by 20 degrees C and has the potential to reduce overall power consumption by some 25 percent.
LTE signals, available in more than 20 distinct bands across the world from various carriers, provide high-speed data transmission that need a high peak-to-average ratio (PAR), and generate higher transmit power, which reduces the efficiency of RF power amplifiers and creates extra heat. The LM3290 and LM3291, which support battery voltages down to 2.5 V, provide high efficiency at higher power output levels and high PAR, while meeting stringent receive band noise requirements in all LTE bands. View an Engineer It video, which outlines how to design with envelope tracking.
Improved bandwidth and battery voltage flexibility is achievable as the device manages all 3G and 4G LTE bandwidths up to 20MHz and battery voltages from 2.5V to 5V.
The devices’ envelope tracking capability helps reduce heat and power consumption by as much as 25 percent; and achieves greater than 90-percent efficiency using advanced power tracking for LTE 25RB.
With the uses of this device smartphones and tablets do not need to depend on maximum power reduction when battery power is low. The integrated DC boost converter in the LM3290 provides maximum transmit power – supporting higher LTE data rates even at lower battery voltage levels.
An analogue and digital interface supports the MIPI eTrak analogue differential front end interface for envelope tracking and a 1.8-V MIPI RFFE digital interface to simplify integration with the industry’s newest RF platforms. The devices also allow seamless transition between envelope tracking and average power tracking operating modes.
These two devices provide high efficiency, low noise, low output impedance and low output ripple voltage at high LTE bandwidths (LTE10 and 20). The devices support a minimum bandwidth of 75MHz – claimed as an industry-first when using envelope tracking — providing high accuracy with good adjacent channel leakage ratio and noise performance.
Texas Instruments
