Multiband LTE will need better RF design
Next generation smartphones are likely to have 40 radios in each handset to support the plethora of mobile standards and the need for multiple radio front-end circuits will have an impact on others parts of the design.
One example is the design of the digital pre-distortion receiver which is shared by multiple power amplifiers (PAs) in 4G LTE systems.
There is a requirement for good isolation between the various radio signal paths to ensure that the PA that is being sampled is not contaminated by other signals.
One supplier, Peregrine Semiconductor has addressed this with a high-isolation SPDT RF switch for LTE wireless basestations.
The PE42420 RF switch has isolation of 64dB at 4GHz. Linearity is specified at IIP3 of 65dBm.
According to Mark Schrepferman, product line director at Peregrine, the need for radio front-ends that are backward-compatible to replace 2G and 3G networks with LTE-ready systems supporting multiple standards and the demand for higher data rates is “requiring improved network performance, which we believe is driving market needs for high-isolation and high-linearity RF components.”
“The PE42420 switch simplifies digital pre-distortion (DPD) loop design, which reduces cost,” said Schrepferman.
The 0.1 to 6GHz PE42420 switch supports 1.8V control logic, enabling the use of lower-voltage, and lower-power, microcontrollers. ESD tolerance of 2kV HBM on all pins eases manufacturing and results in higher reliability of the end product.
The PE42420 switch is available in a 20-pin 4 mm x 4 mm LGA package.