HighBandwidth WideOutputSwing Linear Amplifier for LTE100MHz Envelope Tracking A highbandwidth and wideoutputswing linear amplifier (LA) used in envelope tracking supply modulator (ETSM) for LTE100MHz signal tracking is presented. Stacked output stage employs the cascode structure where the lowvoltage core devices realize high bandwidth and the highvoltage IO devices endure large output swing without reliability issues. Feedforward compensation (FFC) is applied to further extend bandwidth and eliminate oscillation caused by package inductance. Reconfigurable design of bias current and supply voltage are used to optimize efficiency. The output swing can reach 0.5V3.0V and peak efficiency of LA for LTE100604020MHz are 24.7138.4038.2842.21%, respectively. The ET supply modulator with the proposed LA can achieve a peak efficiency of 85% LTE100MHz.

Architecture considerations of LTEWCDMA wideband power amplifier for efficiency improvement An enhanced architecture for a broadband power amplifier (PA) for LTE and WCDMA handsets using InGaPGaAs heterojunction bipolar transistor (HBT) process is presented. A twostage PA solution adopting switchable driverstage amplifier without employing input switch is proposed to reduce loss and help with power efficiency improvement. Furthermore, in order to enhance the poweradded efficiency (PAE) at the low output power level, a twochain amplifying structure in parallel has been implemented. For wideband 1.711.98GHz, the fabricated PA shows u003e27dB of Gain and u003e38% of PAE with  16dB of Gain and u003e13% of PAE with u003c20mA of Icq at the Pout of 17dBm for lowpower mode operation. The system power usage efficiency are obviously enhanced with the presented twostage dualchain PA architecture.